Busch M, Mayer U, Jürgens G
Institut für Genetik and Mikrobiologie, Universität München, Federal Republic of Germany.
Mol Gen Genet. 1996 Apr 10;250(6):681-91. doi: 10.1007/BF02172979.
The GNOM gene is required for pattern formation along the main body axis of the embryo in the flowering plant Arabidopsis thaliana. Mutations in the GNOM gene alter the asymmetric division of the zygote and interfere with the formation of distinct apical-basal regions in the developing embryo. We have isolated the GNOM gene by positional cloning, characterised its structure and determined the molecular lesions in mutant alleles. Although the predicted 163 kDa GNOM protein has a conserved domain in common with the yeast secretory protein Sec7p, it is most closely related in size and overall similarity to the product of the yeast YEC2 gene, which is not essential for cell viability. Four fully complementing gnom alleles carry missense mutations in conserved regions, seven partially complementing alleles have premature stop codon mutations and two non-complementing alleles have splice-site lesions. Our results suggest that the GNOM protein acts as a complex of identical subunits and that partial complementation may involve low levels of full-length protein generated by inefficient translational read-through.
在开花植物拟南芥中，GNOM基因对于胚胎沿主体轴的模式形成是必需的。GNOM基因突变会改变合子的不对称分裂，并干扰发育中胚胎不同顶端-基部区域的形成。我们通过定位克隆分离出了GNOM基因，对其结构进行了表征，并确定了突变等位基因中的分子损伤。尽管预测的163 kDa GNOM蛋白与酵母分泌蛋白Sec7p有一个保守结构域相同，但它在大小和整体相似性上与酵母YEC2基因的产物最为接近，而YEC2基因对细胞活力并非必需。四个完全互补的gnom等位基因在保守区域携带错义突变，七个部分互补的等位基因有过早的终止密码子突变，两个非互补等位基因有剪接位点损伤。我们的结果表明，GNOM蛋白作为相同亚基的复合物起作用，并且部分互补可能涉及通过低效翻译通读产生的低水平全长蛋白。
