Khasanov F K, Savchenko G V, Bashkirova E V, Korolev V G, Heyer W D, Bashkirov V I
Institute of Gene Biology, Russian Academy of Sciences, Moscow 117 984, Russia.
Genetics. 1999 Aug;152(4):1557-72. doi: 10.1093/genetics/152.4.1557.
A new DNA repair gene from Schizosaccharomyces pombe with homology to RecA was identified and characterized. Comparative analysis showed highest similarity to Saccharomyces cerevisiae Rad55p. rhp55(+) (rad homologue pombe 55) encodes a predicted 350-amino-acid protein with an M(r) of 38,000. The rhp55Delta mutant was highly sensitive to methyl methanesulfonate (MMS), ionizing radiation (IR), and, to a lesser degree, UV. These phenotypes were enhanced at low temperatures, similar to deletions in the S. cerevisiae RAD55 and RAD57 genes. Many rhp55Delta cells were elongated with aberrant nuclei and an increased DNA content. The rhp55 mutant showed minor deficiencies in meiotic intra- and intergenic recombination. Sporulation efficiency and spore viability were significantly reduced. Double-mutant analysis showed that rhp55(+) acts in one DNA repair pathway with rhp51(+) and rhp54(+), homologs of the budding yeast RAD51 and RAD54 genes, respectively. However, rhp55(+) is in a different epistasis group for repair of UV-, MMS-, or gamma-ray-induced DNA damage than is rad22(+), a putative RAD52 homolog of fission yeast. The structural and functional similarity suggests that rhp55(+) is a homolog of the S. cerevisiae RAD55 gene and we propose that the functional diversification of RecA-like genes in budding yeast is evolutionarily conserved.
从粟酒裂殖酵母中鉴定并表征了一个与RecA具有同源性的新DNA修复基因。比较分析表明，它与酿酒酵母Rad55p的相似性最高。rhp55(+)（粟酒裂殖酵母rad同源物55）编码一个预测的350个氨基酸的蛋白质，分子量为38,000。rhp55Delta突变体对甲基磺酸甲酯（MMS）、电离辐射（IR）高度敏感，对紫外线的敏感性稍低。这些表型在低温下增强，类似于酿酒酵母RAD55和RAD57基因的缺失。许多rhp55Delta细胞伸长，细胞核异常，DNA含量增加。rhp55突变体在减数分裂基因内和基因间重组中表现出轻微缺陷。孢子形成效率和孢子活力显著降低。双突变分析表明，rhp55(+)与芽殖酵母RAD51和RAD54基因的同源物rhp51(+)和rhp54(+)在一条DNA修复途径中起作用。然而，对于紫外线、MMS或γ射线诱导的DNA损伤修复，rhp55(+)与裂殖酵母假定的RAD52同源物rad22(+)处于不同的上位性组。结构和功能上的相似性表明rhp55(+)是酿酒酵母RAD55基因的同源物，我们提出芽殖酵母中RecA样基因的功能多样化在进化上是保守的。
