Prolactin-Inducible Genes of Pigeon Crop

催乳素（PRL）的作用以细胞分化和分化背后的基因表达变化为特征。本研究旨在了解催乳素对鸽子作物组织基因表达改变的诱导作用。这个模型特别有用，因为组织的组织和发育相对简单，而催乳素引起的变化是深刻和迅速的。使用了各种分子方法。我们已经通过体内和体外蛋白合成、克隆、差异杂交、免疫化学探针和与已知基因杂交等方法鉴定了催乳素诱导的特异性基因产物。prl诱导基因表达的机制将是本提案中描述的实验的主题。该作物主要prl诱导cdna的测序将完成，以检查这些基因与已知功能基因的可能关系。这些数据以后在预测基因调控中涉及的序列时也很有用。核径流转录测定和mRNA周转测量将用于确定PRL诱导的mRNA的调控主要是在转录水平还是转录后水平。根据迄今为止的数据，预计大部分调控将发生在转录后。如果是这样，那么控制prl诱导的mRNA衰变的因子的生化性质将通过用作物组织中的细胞质因子重组原生或克隆的prl诱导转录物来研究。产物的衰变将通过杂交或末端标记转录本的电泳来测量。如果转录是PRL控制的主要机制，一个或多个PRL诱导基因的基因组结构将通过Southern分析、基因组克隆、S1定位和测序来确定。本实验将有助于了解作物组织模型中催乳素刺激的机制和底物，并有助于了解这一重要激素的作用机制。

The actions of prolactin (PRL) are characterized by cellular differentiation and the changes of gene expression that underlie that differentiation. This research is directed toward understanding the induction of altered gene expression in pigeon crop tissue by prolactin. This model is especially useful because the tissue organization and development is relatively simple, and the changes prolactin induces are profound and rapid. Various molecular approaches are used. Specific prolactin-induced gene products have been identified by us through in vivo and in vitro protein synthesis, cloning, differential hybridization, immunochemical probes, and hybridization with known genes. The mechanisms responsible for PRL-induced gene expression will be the subject of the experiments described in this proposal. Sequencing of the major PRL-inducible cDNAs from the crop will be completed to examine possible relationships of these genes with genes of known function. These data will also be useful later in making predictions about sequences involved in the regulation of the genes. Nuclear run-off transcription assays and mRNA turnover measurements will be used to determine whether the regulation of PRL- inducible mRNAs is primarily at a transcriptional or post- transcriptional level. Based on data thus far it is expected that a large part of the regulation will be post-transcriptional. If so, the biochemical nature of the factors responsible for controlling PRL-inducible mRNA decay will be studied by reconstituting either native or cloned PRL-inducible transcripts with cytosolic factors from crop tissues. Decay of the products will be measured by either hybridization or electrophoresis of end-labelled transcripts. If transcription is the primary mechanism of PRL control, the genomic structure of one or more of the PRL-inducible genes will be determined by Southern analysis, genomic cloning, S1 mapping and sequencing. The proposed experiments will provide an understanding of the mechanisms and substrates of prolactin stimulation in the crop tissue model, and will contribute to the general understanding of the mechanism of action of this important hormone.