【摘要】 将鼠二甲基甘氨酸脱氨酶样基因（dimethylglycinedehydrogenase-likegene）的部分编码序列对EST数据库进行同源性分析，得到与其显著相似的1个人EST（GenBankH28856）（330bp）。此EST与9q34上的2个gDNA构成的连续重叠群序列（71094hp）95．6％一致。在H28856上设计1对引物，分别与cDNA文库中载体臂上两端的引物PCR，在所得cDNA上再设计引物与cDNA文库载体臂上引物PCR，最终在肝cDNA文库获得1个完整编码区的cDNA序列1970bp（命名为人二甲基甘氨酸脱氢酶样基因Ⅰ型，DMGDHL1a，又称Ⅰ型），其中有1个1428bp的开放阅读框（ORF）。在胎肝文库中得到此基因的另一剪接型式，其cDNA为1475bp（命名为DMGDHL1b，又称Ⅱ型），含1296bp的ORF。经与71094bp重叠群比较，Ⅰ型由14个外显子构成。Ⅱ型可以确定为与Ⅰ型完全相同的第1至第9外显子，其后还有105bp的序列（含编码区58bp）在已有数据库中找不到一致的序列，因此外显子大小分布暂无法确定。人与鼠的核苷酸序列86．4％一致（836bp），而氨基酸序列88％一致（271aa）。因为人类肌氨酸血症基因定位于9q34，我们推测DMGDHL1可能是肌氨酸脱氢酶也即肌氨酸血症的候选基因。更多还原

【Abstract】 Through the analysis of EST database, we obtained one human EST (GenBank: H28856) which showed significant similarity with the partial coding sequence of rat dimethylglycine dehydrogenase gene. This EST was mapped to 9q34 due to 95.6% identity with one genomic sequence (GenBank: AC002295). A pair of primers (HRP-1 / HRP-2) designed on the sequence of the EST were coupled with the primers (λgt10 -5 / λgt10-3) on the vector flanking cloning site respechvely to amplify the 5’ and 3’ cDNA beyond the EST. New primers designed based on novel cDNA sequence overlapped with the sequence within EST H28856 were used for amplification with λgt10-5 and λgt10-3 by the similar way as above untill a complete ORF was obtained. Finally, a 1970hp sequence (termed as dimethylglycine dehydrogenase like gene isoform Ⅰ, DMGDHL1a) containing a 1428hp complete coding sequence from the live cDNA library and 1475hp sequence (isoform Ⅱ, termed as DMGDHL1b) containing a 1296hp complete coding sequence from the fetas live cDNA library were obtained.Fourteen exons were identified in isoform Ⅰ and the first nine exons of isoform Ⅱwhich shared with isoform Ⅰ could be determined too. The last 105hp cDNA sequence of isoform Ⅱ could not be found in the public database, indicating a very large nitron (>123kb) existed between exon 9 and exon 10 of isoform Ⅱ. DMGDHL1 showed highly homology on both cDNA and piano acid level with rat dimethylglycine dehydrogenase (60% idenhty in 135hp and 35% identity in 436 residues respectively).It was reposed that human sarcosinemia gene was mapped at 9q34. Therefore it could be a good candidato gene for the sarcosinemia.更多还原