DNA Initiation Gene, dnaB, of Bacillus Subtilis

染色体复制起始的调控 将对枯草芽孢杆菌进行研究。 现在还不是 很好理解。 该机制可能涉及多个- 嵌入细胞膜的组成结构， 由特定的DNA片段和蛋白质组成。 至于 蛋白质组分、蛋白质的结构和功能 由dnaB操纵子基因编码的基因。 的 dnaB蛋白的功能对于复制是必需的 染色体的起始。 该基因及其侧翼区 已经被克隆并测序了。 dnaB基因被证明是 操纵子的第一个基因，由三个或四个 基因，dnaB，Y-，Z-，可能 基因. 特异性抗血清 针对前三名的比赛已经准备好并将用于 分离由dnaB操纵子的基因编码的蛋白质。 抗体也将用于体外研究。 入会仪式 将尝试分离Y- Z基因 关于涉及的DNA片段， 复制启动时，我们将研究这两种类型的性质 复制起点区域的膜结合。 枯草杆菌染色体和质粒pUB 110。 I型膜 结合是耐盐的，并且依赖于dnaB+基因 功能，而II型结合是盐敏感的， 与dnaB+基因功能无关。 据信该类型 I结合对于生物化学过程的启动是必不可少的 和II型结合对于pUB 110和染色体的 最初被绑定到膜上的结构， 对于复制的启动和 子染色体 I型结合位点似乎位于或靠近 复制起点都在B。枯草杆菌染色体和 pUB 110。 在pUB 110的四个区域发现II型结合 分子和两个区域附近的purA 16基因座，位于 在距枯草B.subtilis的复制起点20.50 kb内 染色体 这些性质和功能意义 绑定将被进一步分析。

The regulation of initiation of chromosome replication in Bacillus subtilis will be investigated . It still is not yet well understood. The mechanism likely involves a multi- component structure inbedded in the cellular membrane which consists of specific DNA fragments and proteins. As for the protein components, the structure and function of the proteins encoded by the dnaB operon genes will be worked out. The function of the dnaB protein is essential for the replication initiation of the chromosome. The gene and its flanking regions have been cloned and sequenced. The dnaB gene turned out to be the first gene of an operon which consists of three or four genes, dnaB, Y-,Z-and possibly genes. Specific antisera against the first three have been prepared and will be used to isolate proteins encoded by the genes of the dnaB operon. Antibodies will be also used for the studies of the in vitro initiation. Attempts will be made to isolate mutants of the Y- and Z-genes. With regard to the DNA fragments involved in the replication initiation, we will study the nature of the two types of membrane binding of the replication origin areas of the B. subtilis chromosome and a plasmid pUB110. The type-I membrane binding is salt-resistant and dependent on the dnaB+ gene function, whereas type-II binding is salt-sensitive and independent of the dnaB+ gene function. It is believed that type I binding is essential for biochemical processes of initiation and type.II binding is important for pUB110 and the chromosomal original to be bound to a structure on the membrane that is essential for both initiation of replication and the partition of daughter chromosomes. The type -I binding site seems to be located at or near the origin of replication both in the B. subtilis chromosome and pUB110. Type-II binding is found in four areas of the pUB110 molecule and in two areas near the purA16 locus that is located within 20.50 kb from the replication origin of the B.subtilis chromosome. The properties and functional significance of these bindings will be analayzed further.