FUNCTIONS OF THE PIF REGION OF THE F SEX FACTOR

这项研究项目的目标是描述Pif区域的特征 F性别因素。该区域在F的启动过程中起着控制作用 在oriV1(包括在该地区)进行复制，并参与 某些致命的噬菌体的流产感染。以下是 主题将被调查：I.Pif区域的遗传学和 Pif基因表达的控制-a)确定Pif基因的数量；b) 鉴定PIF蛋白产物；c)研究PIF蛋白在 未感染和受噬菌体感染的细胞；d)确定位置和功能 E)确定PIF区域的DNA序列； F)绘制PIF表达的转录起始点。二、两国关系 在oriV1的Pif区到F因子的复制。PIF的一部分 区域与F因子复制的起始点oriV1重叠。我们发现了一个 调控PIF基因合成的负控基因pifC 在这一地区的产品。此外，阳性对照蛋白(1和2) 它们在启动质粒复制过程中起作用，似乎是 位于PIF区域附近或之内的。我们将确定PIF是否 基因与阳性对照蛋白形式和操纵子有共同之处 调控区域；b)建立pifC蛋白与 Eichenlab(1)报道的阳性对照蛋白和其他蛋白 由松原的工作分配给这个地区(2)。三、确定 宿主突变影响Pif基因表达的机制基因突变 PIMA基因可以阻止F因子抑制T7的发育。我们将a) 确定PIMA突变是否干扰表达或 Pif区的活性；b)在以下情况下确定PimA蛋白项目 克隆PIMA结构基因；c)研究PIMA与PIMA的相互作用 宿主细胞的其他成分；d)分离PIMA突变体以确定 研究PIMA突变对其他质粒的影响 和染色体操纵子。IV.T7mRNA合成的特性 含有Pif区DNA的细胞感染-我们将重新调查 T7感染F细胞后某些T7晚期基因表达水平的变化 含有Pif区DNA的细胞。将用液体进行定量 标记RNA样品与克隆的T7DNA特定区域的杂交 转移到血浆载体上。

The goal of this research project is to characterize the Pif region of the F sex-factor. This region plays a role in the control of initiation of F replication at oriV1, (included in the region) and is involved in the abortive infection of certain virulent bacteriophages. The following topics will be investigated: I. The Genetics of the Pif Region and the Control of Pif Gene Expression - a) determine the number of Pif genes; b) identify pif protein products; c) study the location of pif proteins in uninfected and phage infected cells; d) determine the location and function of pif regulatory genes; e) determine the DNA sequence of the pif region; f) map transcription start points for pif expression. II. The Relationship of the Pif Region to F Factor Replication at oriV1. A portion of the Pif region overlaps the origin of F factor replication, oriV1. We have found a negative control gene, pifC, which regulates the synthesis of pif gene products in this region. In addition, positive control proteins (1 and 2) which play a role in the initiation of plasmid replication, appear to be located near or within the pif region. We will determine whether the pif genes and the positive control protein form and operon with a common regulatory region; b) establish the relationship of the pifC protein to the positive control protein reported by Eichenlaub (1) and to other proteins assigned to this region by Matsubara's work (2). III. Determination of the Mechanism by which Host Mutations Affect Pif Gene Expression. Mutations in the pimA gene prevent F factor inhibition of T7 development. We will a) establish whether the pimA mutation inteferes with the expression or activity of the Pif region; b) identify the pimA protein project after cloning the pimA structural gene; c) study the interaction of pimA with other components of the host cell; d) isolate pimA mutants to determine the mechanism of pimA; e) study the affect of pimA mutations on other plasmid and chromosomal operons. IV. Characterization of T7 mRNA Synthesis after Infection of Cells Containing Pif Region DNA - we will reinvestigate the level of certain T7 late mRNA species after T7 infection of F- cells and cells containing Pif region DNA. Quantitation will be performed by liquid hybridization of labeled RNA samples to specific regions of T7 DNA cloned onto plasma vectors.