Global gene expression profiling during pituitary thyrotroph, somatotroph, and lactotroph differentiation.. Gallus gallus

The anterior pituitary is comprised of five major hormone-secreting cell types which differentiate during embryonic development in a temporally distinct manner. Microarrays containing 5,128 unique cDNAs expressed in the neuroendocrine system were produced and used to identify genes with potential involvement in onset of thyroid-stimulating hormone beta-subunit, growth hormone, and prolactin gene transcription during chick embryonic development. We identified 352 cDNAs that were differentially expressed (P < 0.05 and the highest mean at least 1.6-fold greater than the lowest mean) on embryonic day 10, 12, 14, or 17, the period of thyrotroph, somatotroph, and lactotroph differentiation in the chicken. Consistent with cellular ontogeny in the chick anterior pituitary gland, thyroid-stimulating hormone beta-subunit mRNA increased steadily between embryonic day 10 and embryonic day 17, growth hormone mRNA increased between embryonic day 12 and embryonic day 17, and PRL mRNA did not increase until embryonic day 17. Expression of 149 cDNAs increased in a manner similar to thyroid-stimulating hormone beta-subunit mRNA and 67 decreased between embryonic day 10 and embryonic day 17, and some of these are likely associated with thyrotroph differentiation. Similarly, expression of 74 and 66 genes changed in a manner over the 4 ages that is consistent with them having a potential role in induction of growth hormone and prolactin mRNA, respectively. Among these candidate genes are numerous transcription factors and signaling molecules that have not previously been implicated in pituitary development. Keywords: time course during development (4 ages) Overall design: Four biological replicates each of chicken pituitary embryonic day 10, embryonic day 12, embryonic day 14, and embryonic day 17 amplified antisense RNA were analyzed using neuroendocrine cDNA microarrays in a reference design. Each experimental sample (embryonic day 10, 12, 14, or 17) was labeled with Cy3 and hybridized with an aliquot of the Cy5 reference pool, which was generated from all sixteen RNA samples.

垂体前叶由五种主要的激素分泌细胞类型组成，这些细胞在胚胎发育过程中以时间特异性的模式完成分化。
本研究构建了包含5128种神经内分泌系统表达独特互补脱氧核糖核酸（cDNA）的微阵列，用于筛选可能参与鸡胚胎发育阶段促甲状腺激素β亚基、生长激素及催乳素基因转录起始过程的候选基因。我们鉴定出352种cDNA在鸡胚胎第10、12、14或17天呈现显著差异表达（P < 0.05，且最高平均表达量至少为最低平均表达量的1.6倍），而这四个时间点恰好覆盖了鸡垂体前叶促甲状腺激素分泌细胞（thyrotroph）、生长激素分泌细胞（somatotroph）与催乳素分泌细胞（lactotroph）的分化窗口期。
与鸡垂体前叶的细胞个体发育规律高度一致：促甲状腺激素β亚基信使核糖核酸（mRNA）在胚胎第10天至第17天之间持续上调；生长激素mRNA的表达水平自胚胎第12天起逐步升高，直至第17天；而催乳素（PRL）mRNA直至胚胎第17天才出现显著表达上调。
其中，149种cDNA的表达变化趋势与促甲状腺激素β亚基mRNA完全一致，另有67种cDNA在胚胎第10天至第17天之间表达下调，此类基因中部分可能与促甲状腺激素分泌细胞的分化过程密切相关。类似地，分别有74种和66种基因在四个时间点的表达变化模式，与其在诱导生长激素和催乳素mRNA表达中的潜在功能相契合。
在上述候选基因中，包含大量此前未被证实与垂体发育相关的转录因子及信号分子。
关键词：发育时间进程（4个时间点）
整体实验设计：采用参考设计策略，使用神经内分泌cDNA微阵列分析鸡胚胎第10、12、14、17天垂体组织的扩增反义RNA样本，每个时间点设置4个生物学重复。每个实验样本（对应胚胎第10、12、14或17天）均以Cy3荧光基团标记，并与由全部16个RNA样本混合制备的Cy5参考池进行杂交。