The Molecular Genetics of the Yeast RAD52 Gene

利文斯顿9603515这项研究利用经典的遗传学和分子遗传学技术来检测酵母的RAD52基因。这种基因对于保护酵母细胞免受电离辐射并帮助它们重组染色体是很重要的。通过对该基因的克隆拷贝进行突变，可以恢复具有不同特性的rad52突变体。已经进行了温度敏感突变，并对其进行了表征。这些突变体对电离辐射条件敏感，但可以重组它们的染色体，这表明RAD52基因的蛋白产物(Rad52p)可能具有多种作用。目前的项目打算研究RAD52生物学的三个方面。首先，为什么改变Rad52p N-末端结构域氨基酸残基的突变与改变C-末端残基的突变有着截然不同的影响？其次，哪些基因编码的蛋白质通过与Rad52p的物理相互作用直接相互作用，或者通过绕过RAD52重组修复途径间接相互作用？第三，Rad52p在启动减数分裂重组的双链断裂过程中扮演什么角色？实验计划从关注冷敏感的rad52突变和这些突变的基因外抑制物开始。另一组实验将利用体外诱变来探索Rad52p和Rad51p之间的相互作用，Rad51p是另一个在修复和重组中起重要作用的基因的蛋白质产物。最后，将检查rad52突变体是否不能处理重组染色体中的减数分裂双链断裂。最近在包括人类在内的其他生物中发现了RAD52基因，这证明了所有生物在配子产生过程中都需要保护自己免受自然辐射的伤害，并适当地分离它们的染色体。

Livingston 9603515 The research investigated in this project utilizes classical genetic and molecular genetic techniques to examine the yeast RAD52 gene. This gene is important to protect yeast cells from ionizing radiation and to aid them in recombining their chromosomes. By mutagenizing a cloned copy of the gene, rad52 mutants with varying properties can be recovered. Temperature sensitive mutations have already been made and characterized. These mutants are conditionally sensitive to ionizing radiation but can recombine their chromosomes, suggesting that the protein product of the RAD52 gene (Rad52p) may have more than one role. The current project intends to examine three aspects of the biology of RAD52. First, why do mutations altering amino acid residues in the N-terminal domain of Rad52p have a drastically different effect from those that change C-terminal residues? Second, what genes encode proteins that interact either directly by physical interaction with Rad52p or indirectly by circumvention of the RAD52 recombinational repair pathway? Third, what role does Rad52p play in processing of double strand breaks made to initiate meiotic recombination? The experimental plan begins with a focus on cold sensitive rad52 mutations and extragenic suppressors of these mutations. Another set of experiments will utilize in vitro mutagenesis to explore the interaction between Rad52p and Rad51p, the protein product of another gene important in repair and recombination. Finally, rad52 mutants will be examined for their inability to process meiotic double strand breaks in recombinant chromosomes. The need of all organisms to defend themselves from natural radiation and to properly disjoin their chromosomes during gamete production has been evidenced by the recent discovery of RAD52 genes in may other organisms including humans.