Evolution of monoblepharidalean fungi based on complete mitochondrial genome sequences
Evolution of monoblepharidalean fungi based on complete mitochondrial genome sequences
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DOI：
10.1093/nar/gkg264
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发表时间：
2003-03-15
影响因子：
14.9
通讯作者：
Lang, BF
中科院分区：
文献类型：
--
作者：
Bullerwell, CE;Forget, L;Lang, BF
我们测定了三种壶菌纲真菌Monoblepharella 15、Harpochytrium 94和Harpochytrium 105的线粒体DNA全序列。我们基于串联线粒体蛋白质序列的系统发育分析证实了Mono blepharella 15与Harpochytrium spp.和Hyaloraphidium curvatum在分类单lepharidales，以压倒性的支持。这四个mtDNA序列编码标准的真菌线粒体基因互补序列，并且像某些其他壶菌真菌一样，编码7-9个tRNA的减少的互补序列，其中一些需要5 '-tRNA编辑才能起作用。高度保守的序列元件被确定上游的几乎所有的蛋白质编码基因的线粒体DNA的单囊藻15和两个Harpochytrium物种。最后，在这些基因组中，鸟苷残基保守在几乎每个蛋白质编码基因的预测ATG或GTG起始密码子的上游。该G残基的出现与线粒体起始tRNA的反密码子环中37位存在非典型胞嘧啶残基相关。基于这四个基因组中的非正统特征，我们提出这些tRNA的CAUC反密码子和GAUG/GGUG密码子之间的4 bp相互作用参与了单核线粒体的翻译起始。有趣的是，一个类似的相互作用也可能涉及在海葵Metridium老年线粒体翻译启动。
We have determined the complete mitochondrial DNA (mtDNA) sequences of three chytridiomycete fungi, Monoblepharella15, Harpochytrium94 and Harpochytrium105. Our phylogenetic analysis based on concatenated mitochondrial protein sequences confirms the placement of Mono blepharella15 together with Harpochytrium spp. and Hyaloraphidium curvatum within the taxonomic order Monoblepharidales, with overwhelming support. These four mtDNA sequences encode the standard fungal mitochondrial gene complement and, like certain other chytridiomycete fungi, encode a reduced complement of 7-9 tRNAs, some of which require 5'-tRNA editing to be functional. Highly conserved sequence elements were identified upstream of almost all protein-coding genes in the mtDNAs of Monoblepharella15 and both Harpochytrium species. Finally, a guanosine residue is conserved upstream of the predicted ATG or GTG start codons of almost every protein-coding gene in these genomes. The appearance of this G residue correlates with the presence of a non-canonical cytosine residue at position 37 in the anticodon loop of the mitochondrial initiator tRNAs. Based on the unorthodox features in these four genomes, we propose that a 4 bp interaction between the CAUC anticodon of these tRNAs and GAUG/GGUG codons is involved in translation initiation in monoblepharidalean mitochondria. Intriguingly, a similar interaction may also be involved in mitochondrial translation initiation in the sea anemone Metridium senile.