Hahn Yoonsoo, Yang Seung Kyoung, Chung Jae Hoon
Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 305-701, South Korea.
Biochim Biophys Acta. 2005 Nov 10;1731(2):125-32. doi: 10.1016/j.bbaexp.2005.09.004. Epub 2005 Oct 12.
PEG1/MEST is a paternally expressed gene in placental mammals. Here, we report identification of zebrafish (Danio rerio) gene mest, an ortholog of mammalian PEG1/MEST. Zebrafish mest encodes a polypeptide of 344 amino acids and shows a significant similarity to mammalian orthologs. Zebrafish mest is present as a single copy in the zebrafish genome and is closely linked to copg2 as in mammals. It is notable that 10 of 11 intron positions in mest are conserved among mammalian PEG1/MEST genes, indicating that the genomic organization and linkage between mest and copg2 loci was established in ancient vertebrates. Zebrafish mest is expressed in blastula, segmentation, and larval stages, exhibiting gradually increased expression as the development proceeds. Allelic expression analysis in hybrid larvae shows that both parental alleles are transcribed. We also observed one-codon alternative splicing involving an alternative usage of the two consecutive splice acceptors of intron 1, generating two protein isoforms with different lengths of a single amino acid.
PEG1/MEST是胎盘哺乳动物中由父系表达的基因。在此，我们报告了斑马鱼（Danio rerio）基因mest的鉴定，它是哺乳动物PEG1/MEST的直系同源基因。斑马鱼mest编码一个由344个氨基酸组成的多肽，与哺乳动物的直系同源物具有显著的相似性。斑马鱼mest在斑马鱼基因组中以单拷贝形式存在，并且像在哺乳动物中一样与copg2紧密连锁。值得注意的是，mest基因11个内含子位置中的10个在哺乳动物PEG1/MEST基因中是保守的，这表明mest与copg2基因座之间的基因组组织和连锁关系在古代脊椎动物中就已确立。斑马鱼mest在囊胚期、体节期和幼虫期表达，随着发育进程表达逐渐增加。对杂交幼虫的等位基因表达分析表明，两个亲本等位基因均被转录。我们还观察到一种单密码子可变剪接，涉及内含子1的两个连续剪接受体的交替使用，产生了两种具有不同单氨基酸长度的蛋白质异构体。
