SUMO4 and its role in type 1 diabetes pathogenesis

Susceptibility to type 1 diabetes (T1D) is determined by interactions of multiple genes with unknown environmental factors. Despite the characterization of over 20 susceptibility regions for T1D, identification of specific genes in these regions is still a formidable challenge. In 2004, we first reported the cloning of a novel, small ubiquitin-like modifier (SUMO) gene, SUMO4, in the IDDM5 interval on chromosome 6q25, and presented strong genetic and functional evidence suggesting that SUMO4 is a T1D susceptibility gene. Subsequent studies have consistently confirmed this association in multiple Asian populations despite controversial observations in Caucasians. In this review, we will update the genetic evidence supporting SUMO4 as a T1D susceptibility gene and discuss the possible explanations for the discrepant associations observed in Caucasians. We will then discuss the mechanisms through which SUMO4 contributes to the pathogenesis of T1D.     

肝细胞癌和癌旁肝组织中PIAS1蛋白表达及其临床意义

目的探讨肝细胞癌(HCC)和癌旁肝组织中信号转导和转录激活因子1(STAT1)抑制因子(PIAS1)的表达及其临床意义。方法利用两步法免疫组织化学技术检测PIAS1蛋白在HCC及其癌旁肝组织的表达。结果PIAS1蛋白在HCC中的阳性率和阳性强度均低于癌旁肝组织(P<0.01);HCC中PIAS1蛋白的表达强度与患者的性别和肿瘤的大小无关(P>0.05),但与肿瘤细胞的分化程度明显相关(P<0.01)。分化越差,表达越弱。结论提示检测PIAS1蛋白对判断HCC的预后具有一定意义,纠正PIAS1蛋白的表达有可能成为HCC基因治疗新策略。     

PIAS2蛋白在不同病理分型的无精子症患者睾丸组织中的表达

目的:探讨PIAS2在不同生精功能状态的人睾丸组织中的表达情况。方法:对80例无精子症患者进行睾丸组织病理检查诊断,根据病理形态的不同分为：生精功能正常或基本正常(n=40)、精子发生低下(n=20)、唯支持细胞综合征(n=20)等。选择上述各型结构完整的睾丸组织,分别应用免疫组化法(SP)对PIAS2在不同生精功能状态的睾丸组织进行研究。结果:PIAS2在各级生精细胞多为强阳性表达,呈深棕黄色;PIAS2在间质细胞及支持细胞表达弱阳性表达或不表达。结论:PIAS2染色强弱与睾丸生精功能的强弱有一定关系,是一个潜在的判断睾丸生精功能的指标。     

PIAS3的Myc融合蛋白真核表达重组质粒的构建

目的：构建PIAS3 （活化型STAT3抑制蛋白）的Myc融合蛋白真核表达重组质粒，并表达融合蛋白Myc-PIAS3。方法： 采用PCR方法，扩增鼠PIAS3基因全长cDNA编码区序列。将该1 851 bp的特异性片段连接到T载体上，将其亚克隆至pCMV-Myc真核表达载体的SalⅠ和NotⅠ位点之间。将pCMV-Myc-PIAS3重组质粒转染前列腺癌PC3细胞，利用Myc抗体通过Western blotting法检测融合蛋白Myc-PIAS3的表达。结果：重组pCMV-Myc-PIAS3质粒通过酶切和测序鉴定了其正确性。EcoRⅠ酶切鉴定时有4 357和1 318 bp 2条带，XbaⅠ酶切鉴定时有3 291 bp和2 384 bp 2条带，与预期结果一致。测序结果显示，13个氨基酸Myc在N端，然后是阅读框架正确的PIAS3的基因序列。pCMV-Myc-PIAS3重组质粒转染PC3细胞，利用Myc抗体通过Western blotting法检测融合蛋白Myc-PIAS3的表达，在相对分子质量68 000处检测到特异的蛋白表达条带。结论：成功构建pCMV-Myc-PIAS3重组质粒，并表达融合蛋白Myc-PIAS3。     

Regulation of early Xenopus development by the PIAS genes

Originally identified as cytokine inhibitors, protein inhibitors of activated STAT (PIAS) are shown to regulate activities of a plethora of proteins and influence diverse processes such as immune response, cancer formation, and cell cycle progression. However, the roles of PIAS during vertebrate embryogenesis are less understood. In this study, we report isolation and initial characterization of all four PIAS genes from Xenopus laevis. The Xenopus PIAS genes are expressed throughout early development and have overlapping and distinct expression patterns, with, for example, high levels of PIAS2 in the notochord and strong expression of PIAS4 in the neural and neural crest derivatives. Overexpression of PIAS disrupts mesoderm induction and impairs body axis formation. PIAS proteins have differential ability to regulate signals from the growth factors activin, bone morphogenetic protein 4 (BMP4), and Wnt8. Our data suggest that Xenopus PIAS play important roles in mesodermal induction and patterning during early frog development. Developmental Dynamics 240:2120–2126, 2011. © 2011 Wiley‐Liss, Inc.