Van As P, Buys N, Onagbesan O M, Decuypere E
Laboratory for Physiology & Immunology of Domestic Animals, Catholic University of Leuven, Kardinaal Mercierlaan 92, Heverlee, B-3001, Belgium.
Gen Comp Endocrinol. 2000 Nov;120(2):127-36. doi: 10.1006/gcen.2000.7529.
Pit-1 is a pituitary-specific POU-domain DNA binding factor, which binds to and transactivates promoters of growth hormone (GH)-, prolactin (PRL)-, and thyroid-stimulating hormone-beta (TSHbeta)-encoding genes. Pit-1 has been identified in several mammalian species. In birds, it has been identified only in the turkey and chicken pituitary. Several (gg) Pit-1 cDNA sequences have been identified in the anterior pituitary of the chicken (Gallus domesticus). As in turkey, three different transcripts (ggPit-1*, ggPit-1beta*, and ggPit-1W*) of the Pit-1 gene were identified. This suggests that the chicken pituitary expresses more variants than reported earlier. Previous studies have concentrated on expressions during posthatch life of the turkey and chicken. The present study has determined the ontogeny of Pit-1 during the embryonic life of the chicken (day 1-day 21 of incubation). The mRNA for Pit-1 was first detected in the pituitary on day 5 of embryonic life. The expression of the mRNA was maintained until hatch. The presence of Pit-1 at this stage of embryonic development suggests that Pit-1 may be physiologically important during embryonic development of birds, as it precedes the gene expression and secretion of GH, PRL, and TSHbeta. A similar sequence for the expression of Pit-1 relative to GH and PRL during embryonic/fetal development has been reported for rodents.
Pit-1是一种垂体特异性的POU结构域DNA结合因子，它能与生长激素（GH）、催乳素（PRL）和促甲状腺激素β（TSHβ）编码基因的启动子结合并使其反式激活。Pit-1已在多种哺乳动物中被鉴定出来。在鸟类中，仅在火鸡和鸡的垂体中被鉴定出来。在鸡（家鸡）的垂体前叶中已鉴定出多个（gg）Pit-1 cDNA序列。与火鸡一样，鉴定出了Pit-1基因的三种不同转录本（ggPit-1*、ggPit-1β和ggPit-1W）。这表明鸡垂体表达的变体比早期报道的更多。先前的研究集中在火鸡和鸡孵化后的生命过程中的表达情况。本研究确定了鸡胚胎期（孵化第1天至第21天）Pit-1的个体发生情况。胚胎期第5天在垂体中首次检测到Pit-1的mRNA。该mRNA的表达一直维持到孵化。胚胎发育这一阶段存在Pit-1表明，Pit-1在鸟类胚胎发育过程中可能具有重要生理作用，因为它先于GH、PRL和TSHβ的基因表达及分泌。对于啮齿动物，在胚胎/胎儿发育过程中已报道了Pit-1相对于GH和PRL表达的类似序列。
