GASTRIN-RELEASING PEPTIDE GENE EXPRESSION

蛙皮素一种两栖动物肽蛙皮素的哺乳动物等效物，命名为 胃泌素释放肽（GRP）具有强大的生物学作用，包括 几种肠肽激素的释放，与神经调节 作用 GRP还诱导细胞增殖，表明在生长中的作用 调控 GRP已经在哺乳动物的脑、肠、胎儿肺和胎儿肺中被发现。 神经内分泌（NE）肿瘤。 已经对人GRP的三种mRNA进行了测序。 分离自人肺NE肿瘤，所有这些都编码GRP，但不同 在proGRP的C-末端延伸肽中，由于19或21个碱基 插入/缺失剪接事件。 该项目的主要目标是 以确定大鼠基因的序列和发育表达 编码GRP。 这将允许分析组织特异性GRP基因 在大鼠胚胎发育中的表达，这应该阐明GRP在正常发育中的作用。 哺乳动物的生长和发育，以及肿瘤形成。 初步研究 的人胎肺发育已证明峰值免疫反应性GRP 在NE细胞中，在妊娠18至24周，其遵循峰值mRNA水平 在16至22周，并与肺小管期相关 增长 具体目标是：（1）完成大鼠GRP基因的测序 基因，以澄清可能的RNA剪接变体的确切结构。 (2)正常大鼠组织特异性基因表达谱分析 胚胎发生：在通过RNA印迹和S1作图的全组织匀浆中， 在胚胎组织切片中，通过原位杂交， 定位细胞特异性GRP mRNA。 将使用大鼠GRP和proGRP的抗血清， 提出并用于免疫过氧化物酶研究，以与原位 在连续胚切片上杂交。 必须确定 C-末端肽是否也表达，因为这些肽可能具有 生物功能。 GRP-免疫电镜和GRP受体 将进行类似的放射自显影，以进一步澄清GRP的 生理作用。 (3)以确定GRP是否参与了 通过原位杂交和免疫组织化学分析， GRP和C末端肽。 重点将放在肺部肿瘤上， 其中GRP被认为是潜在的自分泌生长因子。 因此，GRP基因可以在发育组织中瞬时表达， 细胞分化中的程序化基因调控的一部分，以及 对这种表达的分析可以阐明基因失调的机制 在肿瘤发生中。

A mammalian equivalent of the amphibian peptide bombesin, designated gastrin-releasing peptide (GRP), has potent biological effects, including release of several gut peptide hormones, consistent with a neuroregulatory role. GRP also induces cell proliferation, suggesting a role in growth regulation. GRP has been found in mammalian brain, gut, fetal lung, and neuroendocrine (NE) tumors. Three mRNAs for human GRP(s) have been isolated from human pulmonary NE tumors, all of which encode GRP but differ in the C-terminal extension peptide of proGRP, due to a 19 or 21 base insertion/deletion splicing event. The major objective of this project is to determine the sequence and developmental expression of the rat gene encoding GRP. This will allow analyses of tissue-specific GRP gene expression in rat embryogenesis, which should clarify GRP's role in normal mammalian growth and development, as well as in neoplasia. Initial studies of human fetal lung development have demonstrated peak immunoreactive GRP in NE cells at 18 to 24 weeks of gestation, which follows peak mRNA levels at 16 to 22 weeks and correlates with the canalicular period of lung growth. My specific aims are: (1) to complete sequencing of the rat GRP gene, to clarify the exact structure of possible RNA splicing variants. (2) To analyze patterns of tissue-specific gene levels in normal rat embryogenesis: in whole tissue homogenates by RNA blotting and S1 mapping, and in embryo tissue sections by in situ hybridization to precisely localize cell-specific GRP mRNA. Antisera to rat GRP and proGRP(s) will be raised and used for immunoperoxidase studies to be correlated with in situ hybridization on serial embryo sections. It will be important to determine whether C-terminal peptides are also expressed, as these may have biological functions. GRP-immunoelectron microscopy and GRP receptor autoradiography will be similarly carried out to further clarify GRP's physiological role. (3) to determine GRP's involvement in pathological processes by in situ hybridization and immunohistochemical analyses for both GRP and C-terminal peptides. The major focus will be on lung tumors, where GRP has been implicated as a potential atuocrine growth factor. Thus, GRP gene(s) may be transiently expressed in developing tissues as part of programmed gene regulation in cellular differentiation, and analyses of this expression may elucidate mechanisms of gene deregulation in oncogenesis.