An interaction between U2AF 65 and CF I(m) links the splicing and 3' end processing machineries

The protein factor U2 snRNP Auxiliary Factor (U2AF) 65 is an essential component required for splicing and involved in the coupling of splicing and 3' end processing of vertebrate pre-mRNAs. Here we have addressed the mechanisms by which U2AF 65 stimulates pre-mRNA 3' end processing. We identify an arginine/serine-rich region of U2AF 65 that mediates an interaction with an RS-like alternating charge domain of the 59 kDa subunit of the human cleavage factor I (CF I(m)), an essential 3' processing factor that functions at an early step in the recognition of the 3' end processing signal. Tethered functional analysis shows that the U2AF 65/CF I(m) 59 interaction stimulates in vitro 3' end cleavage and polyadenylation. These results therefore uncover a direct role of the U2AF 65/CF I(m) 59 interaction in the functional coordination of splicing and 3' end processing.     

Effect of silicon-doped calcium phosphate cement on angiogenesis based on controlled macrophage polarization

Vascularization is an important early indicator of osteogenesis involving biomaterials.Bone repair and new bone formation are associated with extensive neovascu...     

The Wilms Tumor Gene,Wt1, Is Critical for Mouse Spermatogenesis via Regulation of Sertoli Cell Polarity and Is Associated with Non-Obstructive Azoospermia in Humans

Azoospermia is one of the major reproductive disorders which cause male infertility in humans; however, the etiology of this disease is largely unknown. In the present study, six missense mutations of WT1 gene were detected in 529 human patients with non-obstructive azoospermia (NOA), indicating a strong association between WT1 mutation and NOA. The Wilms tumor gene, Wt1, is specifically expressed in Sertoli cells (SCs) which support spermatogenesis. To examine the functions of this gene in spermatogenesis, Wt1 was deleted in adult testis using Wt1^flox and Cre-ER^TM mice strains. We found that inactivation of Wt1 resulted in massive germ cell death and only SCs were present in most of the seminiferous tubules which was very similar to NOA in humans. In investigating the potential mechanism for this, histological studies revealed that the blood–testis barrier (BTB) was disrupted in Wt1 deficient testes. In vitro studies demonstrated that Wt1 was essential for cell polarity maintenance in SCs. Further studies found that the expression of cell polarity associated genes (Par6b and E-cadherin) and Wnt signaling genes (Wnt4, Wnt11) were downregulated in Wt1 deficient SCs, and that the expression of Par6b and E-cadherin was regulated by Wnt4. Our findings suggest that Wt1 is important in spermatogenesis by regulating the polarity of SCs via Wnt signaling pathway and that WT1 mutation is one of the genetic causes of NOA in humans.     

枸杞多糖对H5N1流感全病毒灭活疫苗的体液免疫增强作用

探讨枸杞多糖(Lycium barbarum polysaccharide,LBP)作为佐剂对H5亚型流感病毒全病毒灭活疫苗的体液免疫增强效果。将流感病毒A/Vietnam/1194/2004(H5N1)灭活疫苗与不同剂量的枸杞多糖混合后以腹腔注射的方式共同免疫小鼠,免疫后三周收集血清用于特异性抗体检测。实验中设立氢氧化铝佐剂组作对照共同评价LBP作为佐剂的免疫增强效果。结果显示,小鼠血清中针对H5灭活疫苗的特异性抗体水平在一定范围内随着LBP剂量的增加而提高。LBP在800μg剂量时血清特异性抗体水平较无佐剂组显著增强,并与氢氧化铝佐剂组大致相当。因而,LBP有可能成为一种有效的流感灭活疫苗免疫佐剂。     

Genomic analysis of anti-hepatitis B virus (HBV) activity by small interfering RNA and lamivudine in stable HBV-producing cells

Hepatitis B virus (HBV) causes acute and chronic hepatitis and hepatocellular carcinoma. Small interfering RNA (siRNA) and lamivudine have been shown to have anti-HBV effects through different mechanisms. However, assessment of the genome-wide effects of siRNA and lamivudine on HBV-producing cell lines has not been reported, which may provide a clue to interrogate the HBV-cell interaction and to evaluate the siRNA's side effect as a potential drug. In the present study, we designed seven siRNAs based on the conserved HBV sequences and tested their effects on the expression of HBV genes following sorting of siRNA-positive cells. Among these seven siRNAs, siRNA-1 and siRNA-7 were found to effectively suppress HBV gene expression. We further addressed the global gene expression changes in stable HBV-producing cells induced by siRNA-1 and siRNA-7 by use of human genome-wide oligonucleotide microarrays. Data from the gene expression profiling indicated that siRNA-1 and siRNA-7 altered the expression of 54 and 499 genes, respectively, in HepG2.2.15 cells, which revealed that different siRNAs had various patterns of gene expression profiles and suggested a complicated influence of siRNAs on host cells. We further observed that 18 of these genes were suppressed by both siRNA-1 and siRNA-7. Interestingly, seven of these genes were originally activated by HBV, which suggested that these seven genes might be involved in the HBV-host cell interaction. Finally, we have compared the effects of siRNA and lamivudine on HBV and host cells, which revealed that siRNA is more effective at inhibiting HBV expression at the mRNA and protein level in vitro, and the gene expression profile of HepG2.2.15 cells treated by lamivudine is totally different from that seen with siRNA.