A previous study has demonstrated a significant decrease in the TCRζ gene expression level in chronic myeloid leukemia (CML); thus, we further investigated the expression of TCRζ-regulating factors, the distribution of the TCRζ 3' untranslated region (3'-UTR) splice variants, and the expression level and correlation of the alternative splicing factor/splicing factor 2 (ASF/SF-2), FcεRIγ and ZAP-70 genes. TCRζ 3'-UTR splice variants were identified in peripheral blood mononuclear cells (PBMCs) from 14 healthy individuals, 40 patients with CML and 22 patients with CML in complete remission (CML-CR) by RT-PCR. The expression level of the TCRζ, FcεRIγ, ASF/SF-2 and ZAP-70 genes was analyzed by real-time quantitative PCR. While the expression of TCRζ gene in the CML group was significantly lower than that in the healthy individual and CML-CR groups, a significantly higher expression of the FceRIγ and ASF/SF-2 genes was found in the CML group. Two types of splicing forms were detected in all of the healthy individual CML-CR cases: wild type (WT) TCRζ 3'-UTR and alternatively splieced (AS) TCRζ 3'-UTR which have been alternatively splieced in the WT TCRζ 3'-UTR . However, 35% of the CML cases contained only the wild type TCRζ 3'-UTR isoform. Based on the TCRζ 3'-UTR isoform expression characteristic, we divided the patients with CML into two subgroups: the WT+AS- CML group, containing patients that express only the wild type TCRζ 3'-UTR, and the WT+AS+ CML group, which contained patients that expressed two TCRζ 3'-UTR isoforms. A significantly different ASF/SF-2 and FcεRIγ gene expression pattern was found between the WT+AS- and WT+AS+CML groups. We concluded that defective TCRζ expression may be characterized in the WT+AS-and WT+AS+CML subgroups by the different gene expression pattern. The overexpression of ASF/SF2, which alternatively splices the TCRζ 3'-UTR, is thought to participate in feedback regulation. The characteristics of TCRζ 3'-UTR alternative splicing may be a novel immunological marker for the evaluation of the CML immune status.

Available data suggest that the Varicella-Zoster virus (VZV) IE4 protein acts as an important regulator on VZV and cellular genes expression and could exert its functions at post-transcriptional level. However, the molecular mechanisms supported by this protein are not yet fully characterized. In the present study, we have attempted to clarify this IE4-mediated gene regulation and identify some cellular partners of IE4. By yeast two-hybrid and immunoprecipitation analysis, we showed that IE4 interacts with three shuttling SR proteins, namely ASF/SF2, 9G8 and SRp20. We positioned the binding domain in the IE4 RbRc region and we showed that these interactions are not bridged by RNA. We demonstrated also that IE4 strongly interacts with the main SR protein kinase, SRPK1, and is phosphorylated in in vitro kinase assay on residue Ser-136 contained in the Rb domain. By Northwestern analysis, we showed that IE4 is able to bind RNA through its arginine-rich region and in immunoprecipitation experiments the presence of RNA stabilizes complexes containing IE4 and the cellular export factors TAP/NXF1 and Aly/REF since the interactions are RNase-sensitive. Finally, we determined that IE4 influences the export of reporter mRNAs and clearly showed, by TAP/NXF1 knockdown, that VZV infection requires the TAP/NXF1 export pathway to express some viral transcripts. We thus highlighted a new example of viral mRNA export factor and proposed a model of IE4-mediated viral mRNAs export.

African swine fever (ASF) has persisted in Eastern Europe since 2007, and two endemic zones have been identified in the central and southern parts of the Russian Federation. Moderate- to low-virulent ASF virus isolates are known to circulate in endemic ASF-affected regions. To improve our knowledge of virus transmission in animals recovered from ASF virus infection, an experimental in vivo study was carried out. Four domestic pigs were inoculated with the NH/P68 ASF virus, previously characterized to develop a chronic form of ASF. Two additional in-contact pigs were introduced at 72 days post-inoculation (dpi) in the same box for virus exposure. The inoculated pigs developed a mild form of the disease, and the virus was isolated from tissues in the inoculated pigs up to 99 dpi (pigs were euthanized at 36, 65, 99 and 134 dpi). In-contact pigs showed mild or no clinical signs, but did become seropositive, and a transient viraemia was detected at 28 days post-exposure (dpe), thereby confirming late virus transmission from the inoculated pigs. Virus transmission to in-contact pigs occurred at four weeks post-exposure, over three months after the primary infection. These results highlight the potential role of survivor pigs in disease maintenance and dissemination in areas where moderate- to low-virulent viruses may be circulating undetected. This study will help design better and more effective control programmes to fight against this disease.

The underestimates of NF1 gene mutations in neurofibromatosis 1 (NF1) have been attributed to the large size of the NF1 gene, the considerable frequency of gross deletions and the common occurrence of splicing defects that are only detectable by cDNA analysis. We here report on a patient with severe NF1 showing at RT-PCR analysis the expected fragment from exon 4b to 8 together with a shortened one with the in-frame skipping of exon 7. Sequencing of the corresponding genomic fragment revealed a G->>A transition and a C->>A transversion at nucleotide positions 57 and 58 of the 174-bp long exon 7, neither of which was present in the proband's parents or 50 healthy controls. No other variation was found in the entire NF1 coding sequence. The use of previously established sequence matrices for the scoring of putative ESE motifs showed that the adjacent silent and missense mutations are located within highly conserved overlapping stretches of seven nucleotides with a close similarity to the ESE-specific consensus sequences recognised by the SC35 and SF2/ASF SR proteins. The combined occurrence of both consecutive alterations decreases the motif score for both SF2/ASF and SC35 below their threshold levels. As the aberrant transcript is consistently expressed, a protein lacking 58 amino acids is predicted. Thus the contiguous internal exon 7 mutations are suggested to cause exon 7 skipping as a result of the mis-splicing caused by abrogation of functional ESEs.

We aimed to estimate primary sensory evoked potential (EP) amplitude, amplitude-intensity functions and habituation in migraine patients compared with healthy control subjects and to investigate the possible relation to check size, sound and light discomfort thresholds, and the time to the next attack. Amplitudes of cortical visual evoked potentials (VEP, check size 8' and 33'), cortical long latency auditory evoked potential (AEP NIP1; 40, 55 and 70 dB SL tones) and brainstem auditory evoked potential (BAEP wave IV-V; 40, 55 and 65 dB SL clicks) were recorded and analysed in a blind and balanced design. The difference between the response to the first and the second half of the stimulus sequence was used as a measure of habituation. Twenty-one migraine patients (16 women and five men, mean age 39.3 years, six with aura, 15 without aura) and 22 sex- and age-matched healthy control subjects were studied (18 women and four men, mean age 39.5 years). Low sound discomfort threshold correlated significantly with low levels of BAEP wave IV-V amplitude habituation (r = -0.30, P = 0.05). VEP an AEP amplitudes, habituation, and amplitude-intensity function (ASF) slopes did not differ between groups when ANOVA main factors were considered. Control group VEP habituation was found for small check stimuli (P = 0.04), while potentiation was observed for medium sized checks (P = 0.02). The eight migraine patients who experienced headache within 24 h after the test tended to have increased BAEP wave IV-V ASF slopes (P = 0.08). This subgroup did also have a significant VEP habituation to small checks (P = 0.04). No correlation was found between different modalities. These results suggest that: (i) VEP habituation/potentiation state and brainstem activatio state may depend on the attack-interval cycle in migraine; (ii) VEP habituation/ potentiation may depend on spatial stimulus frequency; (iii) phonophobia (and possibly photophobia) may depend more on subcortical (brainstem) function than on cortical mechanisms; (iv) low cortical preactivation in migraine could not be confirmed; (v) EP habituation and ASF analysis may reflect sensory modality-specific, not generalized, central nervous system states in migraine and healthy control subjects.

A non-haemadsorbing (non-HAD) ASF virus (ASFV) genotype II, namely Lv17/WB/Rie1, was isolated from a hunted wild boar in Latvia in 2017. Domestic pigs experimentally infected with the non-HAD ASFV developed a nonspecific or subclinical form of the disease. Two months later, these animals were fully protected when exposed to other domestic pigs infected with a related virulent HAD genotype II ASFV.

The rapid and reliable detection of African swine fever virus (ASFV) is essential both for timely implementation of control measures to prevent the spread of disease, and to differentiate African swine fever (ASF) from other pig disease with similar clinical presentations. Many virological tests are currently available for the detection of ASFV (live virus), antigen and genome, including virus isolation, ELISA, fluorescent antibody, polymerase chain reaction (PCR) and isothermal assays. In recent years real-time PCR (rPCR) has become one of the most widely used formats for virological diagnosis providing sensitive, specific and swift detection and quantification of ASFV DNA. The ability to integrate rPCR into automated platforms increases sample throughput and decreases the potential for cross-contamination. In more recent years isothermal assays, which are a lower-cost alternative to PCR more suitable for use in non-specialised or mobile laboratories, have been developed for the detection of ASFV, however these assays have not been fully validated for routine use in the field. The performance of all virological detection assays in ASF diagnostics, as well as prospects for improving diagnostic strategies in the future, are discussed and reviewed in this chapter.

Alternative splicing involving intron retention plays a key role in the regulation of gene expression. We previously reported that the alternatively spliced short isoform of endoglin (S-endoglin) is induced during the aging or senescence of endothelial cells by a mechanism of intron retention. In this work, we demonstrate that the alternative splicing factor or splicing factor-2 (ASF/SF2) is involved in the synthesis of endoglin. Overexpression of ASF/SF2 in endothelial cells switched the balance between the two endoglin isoforms, favoring the synthesis of S-endoglin. Using a minigene reporter vector and RNA immunoprecipitation experiments, it was shown that ASF/SF2 interacts with the nucleotide sequence of the endoglin minigene, suggesting the direct involvement of ASF/SF2. Accordingly, the sequence recognized by ASF/SF2 in the endoglin gene was identified inside the retained intron near the consensus branch point. Finally, the ASF/SF2 subcellular localization during endothelial senescence showed a preferential scattered distribution throughout the cytoplasm, where it interferes with the activity of the minor spliceosome, leading to an increased expression of S-endoglin mRNA. In summary, we report for the first time the molecular mechanisms by which ASF/SF2 regulates the alternative splicing of endoglin in senescent endothelial cells, as well as the involvement of ASF/SF2 in the minor spliceosome.

In an effort to identify arthropods that might serve as vectors and perhaps reservoirs of African swine fever virus (ASFV) if it were to enter the U.S.A., the blood-sucking insect Triatoma gerstaeckeri and four species of ticks of the genus Ornithodoros were established in colonies capable of reproducing in numbers sufficient to enable thorough studies to be made of their ASFV vector potentials. A nymphal stage of T. gerstaeckeri carried the virus for 41 days and retained it through one molt, but was unable to transmit it to susceptible pigs. Studies on O. coriaceus revealed that the species is able to harbor and transmit the virus for greater than 440 days, passing it trans-stadially from the first nymphal stage to the adult, sustaining it through at least four molts. Trans-ovarial passage was not demonstrated and nearly 40% of the ticks died, apparently, of the ASFV infection. O. turicata collected in Florida was also found to be capable of becoming infected with ASFV and transmitting it by bite to susceptible pigs. O. puertoricensis collected during the ASF eradication programs in the Dominican Republic and Haiti was not only readily infected experimentally, but it was also able to transmit the virus trans-stadially and trans-ovarially. However, ASFV was not isolated from any of the 350 O. puertoricensis collected in the Dominican Republic and Haiti. O. parkeri from a long-established laboratory colony were able to carry the virus through at least one molt, but they were unable to transmit it to susceptible pigs.

Transboundary animal diseases pose a serious risk to the world animal agriculture and food security and jeopardize international trade. The world has been facing devastating economic losses from major outbreaks of transboundary animal diseases (TADs) such as foot-and-mouth disease, classical swine fever, rinderpest, peste des petits ruminants (PPR), and Rift Valley fever. Lately the highly pathogenic avian influenza (HPAI) due to H5N1 virus, has become an international crisis as all regions around the world can be considered at risk. In the past decades, public health authorities within industrialized countries have been faced with an increasing number of food safety issues. The situation is equally serious in developing countries. The globalization of food (and feed) trade, facilitated by the liberalization of world trade, while offering many benefits and opportunities, also represents new risks. The GF-TADs Global Secretariat has carried out several regional consultations for the identification of priority diseases and best ways for their administration, prevention and control. In the questionnaires carried out and through the consultative process, it was noted that globally, FMD was ranked as the first and foremost priority. Rift Valley fever, and today highly pathogenic avian influenza, are defined as major animal diseases which also affect human health. PPR and CBPP, a disease which is particularly serious in Africa and finally, African swine fever (ASF) and classical swine fever (CSF) are also regionally recognised as top priorities on which the Framework is determined to work. The FAO philosophy--shared by the OIE--embraces the need to prevent and control TADs and emerging diseases at their source, which is most of the time in developing countries. Regional and international approaches have to be followed, and the FAO and OIE GF-TADs initiative provides the appropriate concepts and objectives as well as an organizational framework to link international and regional organizations at the service of their countries to better prevent and control the risks on animal and human health and the economic impact of TADs and emerging animal diseases.

African swine fever virus (ASFV) causes a lethal haemorrhagic disease of pigs. There are conflicting reports on the role of interferon in ASFV infection. We therefore analysed the interaction of ASFV with porcine interferon, in vivo and in vitro. Virulent ASFV induced biologically active IFN in the circulation of pigs from day 3-post infection, whereas low virulent OUR T88/3, which lacks genes from multigene family (MGF) 360 and MGF505, did not. Infection of porcine leucocytes enriched for dendritic cells, with ASFV, in vitro, induced high levels of interferon, suggesting a potential source of interferon in animals undergoing acute ASF. Replication of OUR T88/3, but not virulent viruses, was reduced in interferon pretreated macrophages and a recombinant virus lacking similar genes to those absent in OUR T88/3 was also inhibited. These findings suggest that as well as inhibiting the induction of interferon, MGF360 and MGF505 genes also enable ASFV to overcome the antiviral state.

Since its arrival in the Caucasus and Russia in 2007, African swine fever virus (ASFV) has spread widely and has now affected the EU countries of Estonia, Latvia, Lithuania, Poland and, more recently, the Czech Republic and Romania. The ever-increasing evidence of seropositive wild boar in certain areas suggests that some animals may be surviving for some time or could even be recovering from the disease. This could be due to acquired immunity after the primary infection and/or the presence of related viruses of reduced virulence. To assess these hypotheses, two ASFV field strains from Estonia were studied in vivo in two groups of domestic pigs. After an incubation period of 4 ± 1.6 days, the pigs inoculated intramuscularly with Es15/WB-Tartu 14 ASFV (group 2) developed clinical signs associated with acute disease and succumbed 7 and 11 days post infection (dpi). Pigs inoculated with Es15/WB-Valga-14 ASFV (group 1) had longer incubation times (8 days) than those in group 2 and developed variable clinical signs and lesions compatible with subacute and chronic forms of ASF; they succumbed at 11 and 25 dpi. The in-contact pigs in both groups became infected 7-14 days after exposure and exhibited variable clinical manifestations and pathological findings ranging from acute to chronic disease. Two animals per group recovered completely after infection and were protected against a subsequent homologous virus challenge-exposure performed at 78 dpi. Under experimental conditions, no transmission occurred from the survivors to susceptible sentinel pigs housed together with the survivors 137 days after the primary infection.

The behaviour of free ranging wild boar (Sus scrofa) towards carcasses of their conspecifics potentially infected with African swine fever (ASF) may significantly influence the course of an ASF epidemic. This study aims to better understand the behaviour of wild boar towards their dead fellows. Thirty-two wild boar carcasses on nine study sites in northeast Germany were monitored under field conditions by photo-trapping from October 2015 until October 2016. During this period, a total of 122 160 pictures were taken, thereof 16 111 pictures of wild boar. In both winter and summer, wild boar seemed to be particularly interested in the soil next to and underneath the carcasses. About one third of the visits of wild boar led to direct contact with dead conspecifics. The contacts consisted mostly in sniffing and poking on the carcass. Under the given ecological and climatic conditions, there was no evidence for intra-species scavenging. However, piglets were observed several times chewing bare bones once skeletonization of the carcasses was complete. It must be assumed that all these types of contact may represent a risk of transmission. Both the high tenacity of ASF virus and the long time wild boar carcasses can remain in the environment, allow the persistence of the virus for several months or even years. We therefore consider the rapid detection and removal (or destruction on the spot) of contaminated carcasses as an important control measure against ASF in wild boar.

African swine fever (ASF) is arguably the most dangerous and emerging swine disease worldwide. ASF is a serious problem for the swine industry. The first case of ASF in Russia was reported in 2007. We report an outbreak of ASF in Siberia, Russia, in 2017.

African swine fever virus (ASFV) is the etiological agent of a contagious and often lethal disease of domestic pigs that has significant economic consequences for the swine industry. The disease is devastating the swine industry in Central Europe and East Asia, with current outbreaks caused by circulating strains of ASFV derived from the 2007 Georgia isolate (ASFV-G), a genotype II ASFV. In the absence of any available vaccines, African Swine Fever (ASF) outbreak containment relies on control and culling of infected animals. Limited cross protection studies suggest that in order to ensure a vaccine is effective it must be derived from the current outbreak strain or at the very least from an isolate with the same genotype. Here we report the discovery that deletion of a previously uncharacterized gene, I177L, from the highly virulent ASFV-G produces complete virus attenuation in swine. Animals inoculated intramuscularly with the virus lacking the I177L gene, ASFV-G-ΔI177L, in a dose range of 10² to 10⁶ HAD₅₀ remained clinically normal during the 28 day observational period. All ASFV-G-ΔI177L-infected animals had low viremia titers, showed no virus shedding, developed a strong virus-specific antibody response and, importantly, they were protected when challenged with the virulent parental strain ASFV-G. ASFV-G-ΔI177L is one of the few experimental vaccine candidate virus strains reported to be able to induce protection against the ASFV Georgia isolate, and the first vaccine capable of inducing sterile immunity against the current ASFV strain responsible for recent outbreaks.Importance: Currently there is no commercially available vaccine against African swine fever. Outbreaks of this disease are devastating the swine industry from Central Europe to East Asia, and they are being caused by circulating strains of African swine fever virus derived from the Georgia2007 isolate. Here we report the discovery of a previously uncharacterized virus gene, which when deleted completely attenuates the Georgia isolate. Importantly, animals infected with this genetically modified virus were protected from developing ASF after challenge with the virulent parental virus. Interestingly, ASFV-G-ΔI177L confers protection even at low doses (10² HAD₅₀) and remains completely attenuated when inoculated at high doses (10⁶ HAD₅₀), demonstrating its potential as a safe vaccine candidate. At medium or higher doses (10⁴ HAD₅₀) sterile immunity is achieved. Therefore, ASFV-G-ΔI177L is a novel efficacious experimental ASF vaccine protecting pigs from the epidemiologically relevant ASFV Georgia isolate.

An outbreak in the Caucasus in 2007 initiated the spread of ASFV through Russia and Eastern Europe, subsequently affecting Ukraine, Belarus, Poland, the Baltic States, the Czech Republic, Moldova, Romania and Bulgaria. The declaration of outbreaks in China and Central Europe in August 2018, definitely confirms the serious threat that the extension of ASF represents for the global swine industry and the environment. Despite the efforts of several groups to generate a vaccine against ASFV, currently only control and eradication measures are available based mainly on the early detection and implementation of strict sanitary procedures, including the mass slaughter of animals, both domestic and wild boar. However, the rapid spread of the disease shows that these actions are clearly insufficient to control the current pandemic situation, and the development of a vaccine is urgently required.

Open reading frame P (ORF P), located at the 3' terminus of the 8.5-kb DNA sequence transcribed during latency and almost completely antisense to the gamma(1)34.5 gene, is naturally repressed by infected cell protein 4 (ICP4), the major herpes simplex virus 1 regulatory protein. Earlier studies on cells infected with a mutant in which the expression of ORF P is derepressed have shown that (i) the accumulation of the alpha infected cell proteins 0 (ICP0) and 22 (ICP22), the products of spliced mRNAs, is reduced congruent with the binding of ORF P protein to p32, a component of the ASF/SF2 splicing factors, (ii) ORF P protein colocalizes with spliceosomes, (iii) both gamma(1)34.5 mRNA and protein are virtually undetectable, and (iv) the virus is attenuated on intracerebral inoculation in mice. We report the construction and characterization of two recombinant viruses: R7546, in which ORF P transcription was derepressed and the initiator methionine codon was replaced; and R7547, in which both mutations were repaired to the wild-type genotype. The mutations in R7546 do not alter the amino acid sequence of the gamma(1)34.5 gene. We report that (i) the reduction in the accumulation of gamma(1)34.5 mRNA and protein in cells infected with mutant viruses expressing derepressed ORF P genes reflects the effects of antisense transcription of ORF P rather than a function of ORF P protein, (ii) the attenuated phenotype of the viruses carrying derepressed ORF P genes is due largely to the absence of the gamma(1)34.5 protein, and (iii) the reduction in accumulation of ICP0 and ICP22 requires the expression of ORF P protein.

The aim of this study is to investigate the serum levels of parathyroid hormone (PTH), calcitonin, 1,25 (OH)(2) vitamin D3, estradiol and testosterone in male patients with active renal calcium stone disease compared with controls and investigate their relationship with serum/urinary biochemistry. Male active renal calcium stone formers (ASF) were enrolled from December 2008 to April 2009. Controls were selected from age and sex matched individuals. Two 24-h urine samples and a blood sample were withdrawn from each participant while they were on free diet. Serum 1,25 (OH)(2) vitamin D3 levels in the ASF and control groups were 127 ± 40 and 93 ± 35 pmol/l (p < 0.001). Serum levels of PTH, calcitonin, estradiol and testosterone were not statistically different between the ASF and control groups (all p>> 0.05). Serum 1,25 (OH)(2) vitamin D3 was associated with higher urinary excretion of calcium and phosphorus in ASF patients. Serum levels of calcitonin were related to less urinary excretion of calcium in the control group. Serum testosterone was related to higher urinary excretion of uric acid in ASF patients and to higher urinary excretion of oxalate in the control group. 1,25 (OH)(2) Vitamin D3 is an important hormone in the pathogenesis of recurrent renal calcium stone disease and could increase renal stone risk by increasing the urinary excretion of calcium and phosphorus. There is a possibility of testosterone involvement in the pathogenesis of renal stones through higher urinary uric acid and oxalate excretion.

Twenty-one pigs inoculated with a highly virulent isolate (E70) of African swine fever (ASF) virus were killed 1-7 days later; a further three animals served as uninfected controls. An early increase in TNF-alpha, IL-1alpha, IL-1beta and IL-6 expression was detected in lymphoid organs from infected animals, together with an increase in the serum concentrations of TNF-alpha and IL-1beta. These changes were accompanied by increased apoptosis of lymphocytes, and the presence of infected and uninfected macrophages showing changes indicative of secretory and phagocytic activation. The present study demonstrated an increase in the number of macrophages expressing TNF-alpha, IL-1 and IL-6 in proximity to lymphocytes undergoing apoptosis, supporting previous suggestions that in acute ASF proinflammatory cytokines induce lymphocyte apoptosis.

African swine fever virus (ASFV) was detected in wild boar in eastern Poland in early 2014. So far, 65 cases of ASFV infection in wild boar have been recognised. The methods used for ASFV detection included highly specific real-time PCR with a universal probe library (UPL), enzyme-linked immunosorbent assay (ELISA), and an immunoperoxidase test (IPT) for identification of anti-ASFV antibodies. The positive ASF cases were located near the border with Belarus in Sokółka and Białystok counties. Some of the countermeasures for disease prevention include early ASF diagnosis by ASFV DNA identification as well as detection of specific antibodies by systematic screening. The aim of this study was to assess the current ASF status in a Polish population of wild boar during the last two years (2014-2015).

The aim of this randomized, parallel-group, placebo-controlled, blind clinical study was to examine the dental plaque and the gingivitis inhibitory effects of two low-dose 0.06% chlorhexidine (CHX) preparations in comparison to a commercially available 0.1% CHX solution, an amine fluoride/stannous fluoride (ASF) solution and a water control as an adjunct to the daily mechanical oral-hygiene measures. After prophylaxis, 81 medical students performed their tooth cleaning and were asked to rinse for 30 s, according to the instructions given by the manufacturers with the assigned amount of the following solutions: once daily 10 ml ASF 250 ppm or twice daily each 10 ml CHX 0.06% with fluoride, 10 ml CHX 0.06% without fluoride, 15 ml CHX 0.1% or 100 ml tap water. The plaque index (PlI), the gingival index (GI) and the discoloration index (DI) were taken at day -14 and months (M) 0, 1, 2, 3 and 6. In this study group with good oral hygiene, all test products led to a reduction of the PlI scores when used as supplements to the usual mechanical hygiene measures. At M3 subjects using both the 0.1% as well as the 0.06% CHX showed significantly less plaque accumulation than those using ASF. In the GI a significant difference between the control and 0.1 % CHX was found at M3 and at M6. If a further decrease in the GI is wanted, a minimum concentration of 0.1% CHX for long-term use in association with habitual cleaning is needed, which, however, should be limited to special patients. If maintaining clinical health is the goal, the other solutions are a good alternative to 0.1% CHX because they exhibit less staining.

BACKGROUND

The costs and benefits of spliceosomal introns in eukaryotes have not been established. One recognized effect of intron splicing is its known enhancement of gene expression. However, the mechanism regulating such splicing-mediated expression enhancement has not been defined. Previous studies have shown that intron splicing is a time-consuming process, indicating that splicing may not reduce the time required for transcription and processing of spliced pre-mRNA molecules; rather, it might facilitate the later rounds of transcription. Because the densities of active RNA polymerase II on most genes are less than one molecule per gene, direct interactions between the splicing apparatus and transcriptional complexes (from the later rounds of transcription) are infrequent, and thus unlikely to account for splicing-mediated gene expression enhancement.

OBJECTIVE

The serine/arginine-rich protein SF2/ASF can inhibit the DNA topoisomerase I activity that removes negative supercoiling of DNA generated by transcription. Consequently, splicing could make genes more receptive to RNA polymerase II during the later rounds of transcription, and thus affect the frequency of gene transcription. Compared with the transcriptional enhancement mediated by strong promoters, intron-containing genes experience a lower frequency of cut-and-paste processes. The cleavage and religation activity of DNA strands by DNA topoisomerase I was recently shown to account for transcription-associated mutagenesis. Therefore, intron-mediated enhancement of gene expression could reduce transcription-associated genome instability.

METHODS

Experimentally test whether transcription-associated mutagenesis is lower in intron-containing genes than in intronless genes. Use bioinformatic analysis to check whether exons flanking lost introns have higher frequencies of short deletions.

CONCLUSIONS

The mechanism of intron-mediated enhancement proposed here may also explain the positive correlation observed between intron size and gene expression levels in unicellular organisms, and the greater number of intron containing genes in higher organisms.

METHODS

This article was reviewed by Dr Arcady Mushegian, Dr Igor B Rogozin (nominated by Dr I King Jordan) and Dr Alexey S Kondrashov. For the full reviews, please go to the Reviewer's Reports section.

SR proteins are a family of splicing factors which are important components of spliceosomes. Recent studies suggested that phosphorylation of SR protein might be a key event for the regulation of pre-mRNA splicing and is prevalent in metaphase cells. To investigate the role of cdc2 kinase in cell cycle-dependent phosphorylation of SR protein, we examined its phosphorylation of SF2/ASF, a representative SR protein. SF2/ASF was phosphorylated both by recombinant cdc2 kinase, a cdc2-cyclin B complex, and by cdc2 kinase immunoprecipitated from G2/M phase HeLa cells. In vitro phosphorylation and phosphopeptide mapping of several mutant proteins revealed that cdc2 kinase specifically phosphorylates the RS domain of SF2/ASF with serines 227, 238 and presumably 199 as major phosphorylation sites. These findings suggest the possibility that cdc2 kinase takes part in the cell cycle-dependent phosphorylation of SR protein which regulates the function of spliceosomes.

African swine fever (ASF) is a devastating infectious disease in swine that is severely threatening the global pig industry. An efficacious vaccine is urgently required. Here, we used the Chinese ASFV HLJ/18 as a backbone and generated a series of gene-deleted viruses. The virulence, immunogenicity, safety, and protective efficacy evaluation in specific-pathogen-free pigs, commercial pigs, and pregnant sows indicated that one virus, namely HLJ/18-7GD, which has seven genes deleted, is fully attenuated in pigs, cannot convert to the virulent strain, and provides complete protection of pigs against lethal ASFV challenge. Our study shows that HLJ/-18-7GD is a safe and effective vaccine against ASFV, and as such is expected to play an important role in controlling the spread of ASFV.