Control of Histone H4 Gene Transcription in the Sea Urchin Embryo

温伯格博士正在研究两种基因的转录调控 组蛋白H4基因在不同时间表达， 在海胆胚胎中的程序。早期的H4基因 在卵裂和早期囊胚阶段转录， 在原肠胚表达。他正在研究的晚期H4基因 在低水平表达，直到囊胚中期， 明显增加。主要目标是了解控制 网络参与这两个差异调节 基因.这些研究应该为基因调控提供一个模型 在非常早期的胚胎阶段海胆H4组蛋白基因 具有许多与脊椎动物H4基因相似的特征， 从这里提出的研究中获得的信息应该是 与其他生物中的H4基因调控有关。换句话说， 海胆EH 4基因表达有两个方面， 特别令人兴奋。第一个问题是， 基因的发育控制是负面的。删除， 包括在-150和-140之间10 bp序列，导致 在后囊胚阶段不能抑制转录。之一 该提案的目标是了解EH 4基因的这种模式， 控制特别令人感兴趣的第二个特征是， 只有在绑定时才需要TATA框进行转录， 正作用因子UHF-1的位点被删除。此外，委员会认为， 在体内表达试验中，LH 4 TATA盒不能 取代缺乏UHF的基因中的早期TATA序列， 1个站点。其中一个目标是研究UHF-1、TFIID和 引发剂元件参与引发 转录。这些实验的一般策略是 识别序列元素并测试元素的排列 通过在核提取物中转录或通过使用体内 将基因注入受精卵的表达测定 另一种海胆物种。

Dr. Weinberg is studying the transcriptional regulation of two histone H4 genes which are expressed with different temporal programs in the sea urchin embryo. The early H4 gene is transcribed in the cleavage and early blastula stages and is not expressed at gastrula. The particular late H4 gene he is studying is expressed at a low level until mid-blastula when transcription markedly increases. The major goal is to understand the control network involved in the differential regulation of these two genes. These studies should provide a model for gene regulation at a very early embryonic stage. The sea urchin H4 histone genes have a number of features similar to vertebrate H4 genes and information gained from the research proposed here should be relevant to H4 gene regulation in other organisms. Moveover, there are two aspects of sea urchin EH4 gene expression which are particularly exciting. The first is that a major part of the developmental control of the gene is negative. Deletions which include a 10 bp sequence between -150 and -140 result in a failure to repress transcription at post-blastula stages. One of the goals of the proposal is to understand this mode of EH4 gene control. A second feature which is of special interest is that the TATA box is required for transcription only if the binding site for the positive acting factor UHF-1 is deleted. Moreover, in an in vivo expression assay, the LH4 TATA box cannot substitute for the early TATA sequence in a gene lacking the UHF- 1 site. One of the goals is to investigate how UHF-1, TFIID, and an initiator element are involved in the initiation of transcription. The general strategy of these experiments is to identify sequence elements and test arrangements of the elements by transcription in nuclear extracts or by using an in vivo expression assay in which genes are injected into fertilized eggs of another sea urchin species.