大鼠胰腺发育过程中AFP动态表达的意义

目的:探索大鼠胰腺发育过程中AFP动态表达的意义.方法:采用高密度寡核苷酸芯片对胚胎12.5天(E12.5)、E15.5、E18.5、初生和成年大鼠胰腺进行基因转录水平分析.结果:AFP显著高表达于E18.5大鼠胰腺,AFP在胚胎期的动态表达趋势与胰腺功能细胞标志物以及可能介导AFP促细胞增殖效应的有关信号系统成员的表达趋势一致.结论:AFP在大鼠胰腺发育过程中动态表达的生物学意义可能在于参与胰腺发育调控.     

BTG2基因在大鼠胚胎胰腺不同发育阶段的表达

利用高密度寡核苷酸芯片技术对大鼠胚胎胰腺发育中晚期(E12．5,E18．5,E15．5)调节内外分泌部细胞发育分化及功能代谢的基因的表达趋势进行研究。并用RT-PCR进行验证。用获得的基因信息对:NCBI等公共数据库进行检索,结果发现对细胞的分化、增殖和凋亡起调节作用的BTG2基因在大鼠胚胎胰腺E12．5、E15．5、E18．5天及成年、新生大鼠胰腺中均有表达,且E18．5天的表达量高于其他时期5倍多。推测BTG2可能在大鼠胚胎胰腺内外分泌细胞分化发育的不同阶段起到了促进作用,并参与胚胎胰腺发育晚期的功能代谢完善过程。     

WFS1在大鼠胰腺不同发育阶段的表达

目的:研究WFS1在胰腺发育不同阶段的表达和细胞定位.方法:运用Western Blot技术检测WFS1在大鼠胰腺发育不同阶段的蛋白表达水平;运用免疫荧光检测不同时期WFS1在胰腺的定位.结果:Western Blot结果显示WFSl的蛋白表达量胚胎后期高于新生期,成年期表达量上升;免疫荧光结果显示在不同发育时期WFS1与胰岛β细胞共表达.结论:WFS1在胚胎发育中后期的高表达可能与胰岛形成及功能完善有关,并且可能参与了胰岛重塑.     

大鼠胚胎发育期NBC1 在胰腺的表达与定位

目的:探讨碳酸氢钠协同转运载体(NBC1)在大鼠胰腺胚胎发育期不同阶段核酸、蛋白水平的动态变化以及在腺泡和β细胞的定位表达。方法:采用高密度寡核苷酸芯片对孕12.5 d(E12.5)、E15.5、E18.5、新生和成年胰腺进行基因转录水平分析,用RT-PCR和Western blot分别验证了NBC1核酸和蛋白在E15.5、E18.5、新生和成年时期胰腺中的表达情况,用Double fluorescence immunohistochemistry分析了NBC1在E18.5、新生和成年时期胰腺腺泡和β细胞的定位表达。结果:在大鼠胰腺胚胎发育过程中,NBC1核酸、蛋白在E18.5时特异高表达,新生下降直至成年最低;在腺泡基底侧膜和β细胞膜有强烈的阳性信号,且在成年胰腺中β细胞膜阳性信号较腺泡基底侧膜强。NBC1的表达变化与其功能近似基因的表达趋势相反,而与其协同发挥作用的基因及胰腺特异基因的表达趋势一致。结论:NBC1在胰腺发育过程中不仅与结构形成而且与功能发挥相关。     

Paxillin在大鼠胰腺发育不同时期表达的研究

目的:研究桩蛋白(Paxillin,Pxn)在胰腺发育不同阶段的表达和细胞定位.方法:运用RT-PCR技术检测Pxn在大鼠胰腺发育不同阶段的mRNA表达水平;运用免疫组织化学检测不同时期桩蛋白在胰腺的定位.结果:RT-PCR结果显示Pxn的mRNA表达量胚胎期高于新生和成年期;免疫组织化学结果显示在不同发育时期桩蛋白不仅在外分泌胰腺有表达,而且在胰岛也有表达.结论:具有调节细胞聚集、粘附迁移功能的桩蛋白可能参与出生后胰岛重塑.     

大鼠胰腺发育中原癌基因c-met的表达及蛋白定位

目的:研究原癌基因c-met在大鼠胰腺发育不同阶段的表达及定位.方法:采用RT-PCR技术检测c-met基因在大鼠胰腺不同发育时期:孕15.5天(E15.5)和孕18.5天、新生、生后14天(P14)、P21及成年胰腺的表达.并用免疫组化技术对该基因编码的蛋白-肝细胞生长因子受体c-MET蛋白在胰腺发育不同阶段的定位进行分析.结果:c-met基因在E15.5、E18.5较成年特异性高表达.免疫组化结果显示该基因编码的蛋白c-MET在新生后的胰腺大量定位与胰岛细胞.结论:提示c-met可能在胰腺发育过程中起到调控作用,参与胰腺发育中新生后胰岛结构重塑过程.     

Expression of wnt and frizzled genes during early sea star development

The Wnt signaling pathway is highly conserved across metazoa and has pleiotropic functions in the development of many animals. Binding of a secreted Wnt ligand to its Frizzled (Fz) receptor activates Dishevelled, which then drives one of three major signaling cascades, canonical (β-catenin), calcium, or planar cell polarity signaling. These pathways have distinct developmental effects and function in different processes in different organisms. Here we report the expression of six wnt and three fz genes during embryogenesis of the sea star, Patiria miniata, as a first step in uncovering the roles of Wnt signaling in the development of this organism. wnt3, wnt4, wnt8, and wnt16 are expressed in nested domains in the endoderm and lateral ectoderm from blastula through late gastrula stages; wnt2 and wnt5 are expressed in the mesoderm and anterior endoderm. Expression of different fz paralogs is detected in the mesoderm; posterior endoderm and ectoderm; and anterior ectoderm. Taken together, this suggests that Wnt signaling can occur throughout most of the embryo and may therefore play multiple roles during sea star development.     

Expression of wnt and frizzled genes during early sea star development

The Wnt signaling pathway is highly conserved across metazoa and has pleiotropic functions in the development of many animals. Binding of a secreted Wnt ligand to its Frizzled (Fz) receptor activates Dishevelled, which then drives one of three major signaling cascades, canonical (β-catenin), calcium, or planar cell polarity signaling. These pathways have distinct developmental effects and function in different processes in different organisms. Here we report the expression of six wnt and three fz genes during embryogenesis of the sea star, Patiria miniata, as a first step in uncovering the roles of Wnt signaling in the development of this organism. wnt3, wnt4, wnt8, and wnt16 are expressed in nested domains in the endoderm and lateral ectoderm from blastula through late gastrula stages; wnt2 and wnt5 are expressed in the mesoderm and anterior endoderm. Expression of different fz paralogs is detected in the mesoderm; posterior endoderm and ectoderm; and anterior ectoderm. Taken together, this suggests that Wnt signaling can occur throughout most of the embryo and may therefore play multiple roles during sea star development.     

Expression of ornithine decarboxylase in pancreatic development

We examined the relationship between ornithine decarboxylase (ODC) and growth and differentiation in the developing rat exocrine pancreas. The ODC activity profile showed 2 distinct stages of increases with the first occurred at 14–16 days of age, and a second at 21–23 days of age. Growth parameters evaluated as gains in tissue mass, protein and DNA content in the pancreas indicated a low growth rate soon after birth with a transition to a much more rapid growth rate around the age of 20–21 days, a time corresponded to the second rise in ODC activity. Differentiation parameters evaluated as the accumulation of trypsinogen, amylase and lipase showed different temporal changes. While the rate of accumulation of all three enzymes was relatively low following birth, a rapid rate of accumulation of trypsinogen and amylase started around 15–16 days, a time corresponding to the first rise in ODC activity. Lipase, however, did not show an increase in its accumulation until around age 20 days. These results indicate that a rise in ODC activity is closely associated with growth and differentiation in the developing rat pancreas. To further examine this issue, the steady state levels of ODC mRNA in developing rats were evaluated by Northern blots probed with an ODC cDNA. The developmental profile of ODC mRNA showed a broad peak with a pronounced shoulder occurring at 10 days of age. A higher peak was reached around 20 days of age, then dropped precipitously to a very low level at the age of 24 days. This temporal changes in the level of ODC mRNA show good relationship to the changes in ODC activity suggesting that the control of ODC expression occurs at least in part at the pre-translational level.     

Expression of cell type-specific markers during pancreatic development in the mouse: implications for pancreatic cell lineages

Summary The islet cells of the mammalian pancreas are comprised of four different endocrine cell types, each containing a specific hormone. Islet cells also contain two enzymes of the catecholamine biosynthetic pathway: tyrosine hydroxylase (TH) and aromatic L-amino acid decarboxylase (AADC). The cell lineage relationships of these different cell types have not been examined and it is not known whether, during development, they originate from the same or from different precursor populations. In this study we used immunocytochemical procedures to determine whether developing pancreatic cells express markers common to endocrine and exocrine cell types. We found that acinar cell precursors express AADC prior to the appearance of an exocrine marker and that the expression of AADC in acinar cells persists throughout embryogenesis to the first month of postnatal life. At this time, acinar cells do not contain AADC. We also found that exocrine cells containing AADC never express other islet-cell markers. These findings suggest that while acinar and islet cells both arise from precursor cells containing AADC, these progenitor cells do not express a combined endocrine-exocrine phenotype.