Bagherieh-Najjar Mohammad B, de Vries Onno M H, Kroon Johan T M, Wright Emma L, Elborough Kieran M, Hille Jacques, Dijkwel Paul P
Molecular Biology of Plants, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Kerklaan 30, 9751 NN Haren, The Netherlands.
Plant Mol Biol. 2003 May;52(2):273-84. doi: 10.1023/a:1023968429220.
The Arabidopsis genome contains seven genes that belong to the RecQ family of ATP-dependent DNA helicases. RecQ members in Saccharomyces cerevisiae (SGS1) and man (WRN, BLM and RecQL4) are involved in DNA recombination, repair and genome stability maintenance, but little is known about the function of their plant counterparts. The Arabidopsis thaliana RecQsim gene is remarkably different from the other RecQ-like genes due to an insertion in its helicase domain. We isolated the AtRecQsim orthologues from rice and rape and established the presence of a similar insertion in their helicase domain, which suggests a plant specific function for the insert. The expression pattern of the AtRecQsim gene was compared with the other Arabidopsis RecQ-like members in different tissues and in response to stress. The transcripts of the AtRecQsim gene were found in all plant organs and its accumulation was higher in roots and seedlings, as compared to the other AtRecQ-like members. In contrast to most AtRecQ-like genes, the examined environmental cues did not have a detectable effect on the accumulation of the AtRecQsim transcripts. The budding yeast sgs1 mutant, which is known to be hypersensitive to the DNA-damaging drug MMS, was transformed with the AtRecQsim cDNA. The AtRecQsim gene suppressed the MMS hypersensitivity phenotype of the sgs1 cells. We propose that the Arabidopsis RecQsim gene, despite its unusual structure, exhibits an evolutionary conserved function.
拟南芥基因组包含七个属于依赖ATP的DNA解旋酶RecQ家族的基因。酿酒酵母（SGS1）和人类（WRN、BLM和RecQL4）中的RecQ成员参与DNA重组、修复和基因组稳定性维持，但对其植物同源物的功能了解甚少。由于拟南芥RecQsim基因的解旋酶结构域存在一个插入片段，它与其他类RecQ基因明显不同。我们从水稻和油菜中分离出AtRecQsim的直系同源基因，并确定其解旋酶结构域中存在类似的插入片段，这表明该插入片段具有植物特异性功能。我们比较了AtRecQsim基因与拟南芥其他类RecQ成员在不同组织以及对胁迫反应中的表达模式。在所有植物器官中都发现了AtRecQsim基因的转录本，与其他类AtRecQ成员相比，其在根和幼苗中的积累更高。与大多数类AtRecQ基因不同，所检测的环境信号对AtRecQsim转录本的积累没有可检测到的影响。已知对DNA损伤药物MMS高度敏感的芽殖酵母sgs1突变体用AtRecQsim cDNA进行了转化。AtRecQsim基因抑制了sgs1细胞对MMS的高度敏感表型。我们认为，拟南芥RecQsim基因尽管结构异常，但仍表现出进化上保守的功能。
