摘要
Ptf1a,又名p48,是Ptf1转录因子的一个亚基,为胰腺命运决定与细胞分化必需的转录因子.最近研究发现,Ptf1a表达的丰度变化与发育中胰腺细胞生长、分化和胰岛β细胞数量密切相关.然而,胰腺细胞中Ptf1a的表达调节机制还不清楚.MicroRNAs(miRNAs)是一类约22nt的非编码小RNA,它们通过切割靶mRNA或抑制靶mRNA的翻译调节基因的表达.一些研究提示,miRNAs参与调控胰腺发育的多个过程.因而推测,miRNAs可能在胰腺发育中参与调控Ptf1a的表达变化.为了验证这一假设,结合两个靶基因预测算法的结果,获得4个可能调控Ptf1a表达的miRNAs.随后,利用双荧光素酶报告系统研究发现,预测得到miRNAs中的miR-18a,miR-145和miR-495能通过结合到小鼠Ptf1a mRNA的3′UTR而有效抑制其表达.还利用qRT-PCR和免疫荧光染色实验研究了miR-18a、miR-145和miR-495与Ptf1a在小鼠胰腺发育过程中的表达模式.结果表明,miR-18a,miR-145和miR-495与Ptf1a mRNA及蛋白质的表达成负相关,进一步说明miR-18a,miR-145和miR-495可能在小鼠胰腺发育中调节Ptf1a的表达.
Ptfla, also known as p48, is an important bHLH transcriptional factor, functioning as an integral part of a trimeric protein complex Ptfl, which is essential for fate determination and cell differentiation of pancreas. Recent studies have found that levels of Ptfla in developing pancreas are closely related to the growth and differentiation of pancreatic cells, as well as the number of islet β cells. However, the regulatory mechanism of Ptfl a expression is still elusive. MicroRNAs are a class of approximately 22-nucleotide, non-coding RNAs, which regulate gene expression by cleaving target mRNAs or inhibiting their translation. In addition, some studies have indicated that miRNAs participate in regulating many processes in pancreatic development. Therefore, miRNAs may regulate the expression of Ptfla in developing pancreas. In order to verify this hypothesis, four miRNAs which may regulate the expression of Ptfl a were firstly obtained by overlapping two prediction algorithms. Subsequently, by dual luciferase reporter system in vitro, three of the four miRNAs, miR-18a, miR-145 and miR-495, were proved to effectively inhibit Ptfl a expression, respectively, by binding to the 3＇ UTR of mouse Ptfl a mRNAs. Finally, expression patterns of miR-18a, miR-145 and miR-495 and Ptfl a were detected in the mouse pancreatic development via qRT-PCR and immunofluorescent staining. The results showed that the expression of miR-18a, miR-145 or miR- 495 is negatively correlated with that of Ptfla mRNA and protein. Accordingly, these results indicated that miR-18a, miR-145 and miR-495 may regulate the expression of Ptfl a in developing mouse pancreas.
出处
《生物化学与生物物理进展》
SCIE
CAS
CSCD
北大核心
2009年第12期1607-1612,共6页
Progress In Biochemistry and Biophysics
基金
国家自然科学基金资助项目(30670304)~~
