ROLE OF TESTIS-SPECIFIC HISTONES IN SPERMATOGENESIS

精子发生涉及前体细胞的连续变化， 单倍体精子通过调节有丝分裂，减数分裂， 精子细胞分化事件。在减数分裂过程中， 体细胞组蛋白被生精细胞特异性 组蛋白 该应用程序的主要目标是 研究体细胞和睾丸特异性组蛋白基因调控 以及睾丸特异性组蛋白在组装新的 染色质结构和减数分裂。的 生精细胞特异性转录的相反机制 和S期特异性转录元件的抑制。 睾丸特异性组蛋白TH 2B基因将被研究， 确定细胞所需的DNA序列元件- 特异性转录和核因子的结合位点， 监管要素。DNA元素将是 通过5'或3'侧翼序列的连续缺失鉴定 与报告基因融合的TH 2B基因的序列， 氯霉素乙酰转移酶（CAT）。《禁止酷刑公约》在 TH 2B调节序列的控制将通过以下方法进行检查： 将融合基因导入大鼠生精细胞。的 TH 2B基因具有允许基因表达的DNA元件 但这些元素在细胞周期中被抑制， 细胞。将研究抑制的机制。的 睾丸特异性组蛋白在新染色质组装中的作用 结构和减数分裂将通过引入大鼠H2 B进行研究 和TH 2B基因导入不产生H2 B组蛋白的酵母中。 改变H2 B结合的TH 2B的氨基酸序列 将确定组蛋白与DNA的比例。大鼠H1和TH 1组蛋白基因 并且H1 + H2 B和TH 1 + TH 2B基因的组合也将被 引入酵母细胞，以研究组蛋白 对染色质结构和减数分裂的影响。我们将对H2 A基因进行测序 在TH 2B基因的3'侧，以确定组蛋白基因 编码睾丸特异性H2 A组蛋白

Spermatogenesis involves sequential changes of precursor cells to haploid spermatozoa through regulated mitotic, meiotic, and spermiogenic cell differentiation events. During meiotic process, somatic histones are replaced by spermatogenic cell-specific histones. The major objective of this application is to investigate regulation of somatic and testis-specific histone genes and also the role of testis-specific histones in assembly of new chromatin structure and meiosis during spermatogenesis. The opposing mechanisms of spermatogenic cell-specific transcription and repression of S-phase specific transcription elements in a testis-specific histone TH2B gene will be investigated by determining the DNA sequence elements required for the cell- specific transcription and the binding sites of nuclear factors on the regulatory elements. The DNA elements will be identified by sequential deletions of the 5' or 3' flanking sequence of the TH2B gene fused with a reporter gene, chloramphenicol acetyl transferase (CAT). Expression of CAT under the control of TH2B regulatory sequences will be examined by introduction of the fused genes into rat spermatogenic cells. The TH2B gene has the DNA element(s) which allows the gene expressed in a cell-cycle specific manner but the elements are repressed in the cells. The mechanism of repression will be investigated. The role of testis-specific histones in assembly of new chromatin structure and meiosis will be investigated by introducing rat H2B and TH2B genes into the yeast which do not produce H2B histones. The amino acid sequences of TH2B which alter the binding of H2B histones to DNA will be determined. Rat H1 and TH1 histone genes and also combination of H1 + H2B and TH1 + TH2B genes will be introduced into yeast cells to investigate effects of the histones on chromatin structure and meiosis. We will sequence the H2A gene on the 3' side of TH2B gene to determine if the histone gene encodes the testis-specific H2A histones.