Molecular Analysis of a Nucelar Mutation Affecting Chloroplast Development

高等植物的高叶绿素荧光（hcf）突变体是一类光合活性叶绿体发育所必需的核基因。它们的产物可能包括光合机构的核编码成分，以及辅助因子生物合成和质体基因表达所需的酶和调控基因。一些hcf突变体对膜蛋白组装和类囊体组织有多效性影响。hcf106是玉米中这种突变的一个例子：通过转座子标记克隆了hcf106基因，结果表明该基因产物是一个完整的叶绿体膜蛋白。它有一个单一的跨膜结构域，一个潜在的核苷酸结合位点，但与已知的蛋白质没有其他同源性。来自突变体叶绿体的类囊体膜失去了其特有的横向异质性，并且不能积累类囊体膜蛋白的子集。分析衍生等位基因，次倍体和双突变体将用于遗传定义hcf106病变。免疫定位的亚细胞器分离和免疫电子显微镜将用于研究该蛋白在类囊体组装中的可能作用。光合作用是地球上生命的基础，全面了解这一过程以及叶绿体的生物发生是生物学研究的最重要目标之一。

High chlorophyll flourescent (hcf) mutants of higher plants represent a class of nuclear genes required for the development of photosynthetically active chloroplasts. Their products may include nuclear-encoded components of the photosynthetic apparatus, as well as enzymes and regulatory genes required for co-factor biosynthesis and plastid gene expression. Some hcf mutants have pleiotropic effects on membrane protein assembly and thylakoid organization. hcf106 is an example of such a mutation in maize: The Hcf106 gene has been cloned by transposon tagging, and the gene product shown to be an integral chloroplast membrane protein. It has a single transmembrane domain, a potential nucleotide binding site, but no other homology to known proteins. Thylakoid membranes from mutant chloroplasts have lost their characteristic lateral heterogeneity, and fail to accumulate a subset of thylakoid membrane proteins. Analysis of derivative alleles, hypoploids and double mutants will be used to genetically define the hcf106 lesion. Immunolocalization by suborganellar fractionation and immuno- electron microscopy will be used to investigate the possible roles of this protein in thylakoid assembly. %%% Photosynthesis is the basis of life on the planet Earth and a complete understanding of the process as well as chloroplast biogenesis is one of the most important goals of biological research.