CONSERVED GENE CLUSTERS IN THE HIGHLY REARRANGED CHLOROPLAST GENOMES OF CHLAMYDOMONAS-MOEWUSII AND CHLAMYDOMONAS-REINHARDTII
CONSERVED GENE CLUSTERS IN THE HIGHLY REARRANGED CHLOROPLAST GENOMES OF CHLAMYDOMONAS-MOEWUSII AND CHLAMYDOMONAS-REINHARDTII
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DOI：
10.1007/bf00023556
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发表时间：
1994-02-01
影响因子：
5.1
通讯作者：
TURMEL, M
中科院分区：
文献类型：
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作者：
BOUDREAU, E;OTIS, C;TURMEL, M
我们通过对莫伊斯衣藻和莱茵衣藻叶绿体DNA的部分测序，将其上的基因数目扩展到75个。eugametos和C. moewusii cpDNA并与衣藻叶绿体基因特异性序列杂交。这些基因中只有四个（tscA和三个阅读框架）尚未在任何其他藻类cpDNAs中被鉴定，因此可能是衣原体特有的。虽然C. moewusii和C. reinhardtii cpDNA的不同之处在于复杂的序列重排，38个基因分散在整个基因组中，定义了12个保守的紧密连锁的基因座簇。除了rRNA操纵子之外，这些基因簇中的四个与在其他cpDNA中发现的进化上原始的操纵子有相似之处，实际上代表了这些操纵子的残余。因此，我们的研究结果表明，大多数的祖先细菌操纵子的叶绿体基因组组织的陆地植物和早期发散光合真核生物的特征已被破坏之前出现的多系属衣原体。C. moewusii和C. reinhardtii的cpDNAs，除了那些解释atpA，psbI和rbcL的重新定位，发生在基因组的相应区域。这些重排之一似乎导致了包含rp123、rp12、rps19、rp116、rp114、rp15、rps8和psaA外显子1的祖先区域的破坏。该基因簇与大肠杆菌S10和spe操纵子具有惊人的相似性，跨越C. reinhardtii，而C.毛乌素。
We have extended to about 75 the number of genes mapped on the Chlamydomonas moewusii and Chlamydomonas reinhardtii chloroplast DNAs (cpDNAs) by partial sequencing of the very closely related C. eugametos and C. moewusii cpDNAs and by hybridizations with Chlamydomonas chloroplast gene-specific sequences. Only four of these genes (tscA and three reading frames) have not been identified in any other algal cpDNAs and thus may be specific to Chlamydomonas. Although the C. moewusii and C. reinhardtii cpDNAs differ by complex sequence rearrangements, 38 genes scattered throughout the genome define 12 conserved clusters of closely linked loci. Aside from the rRNA operon, four of these gene clusters share similarity to evolutionarily primitive operons found in other cpDNAs, representing in fact remnants of these operons. Our results thus indicate that most of the ancestral bacterial operons that characterize the chloroplast genome organization of land plants and early-diverging photosynthetic eukaryotes have been disrupted before the emergence of the polyphyletic genus Chlamydomonas. All gene rearrangements between the C. moewusii and C. reinhardtii cpDNAs, with the exception of those accounting for the relocations of atpA, psbI and rbcL, occurred within corresponding regions of the genome. One of these rearrangements seems to have led to disruption of the ancestral region containing rp123, rp12, rps19, rp116, rp114, rp15, rps8 and the psaA exon 1. This gene cluster, which bears striking similarity to the Escherichia coli S10 and spe operons, spans a continuous DNA segment in C. reinhardtii, while it maps to two separate fragments in C. moewusii.