Structure and characterization of human carboxylesterase 1A1, 1A2, and 1A3 genes
Structure and characterization of human carboxylesterase 1A1, 1A2, and 1A3 genes
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DOI：
10.1097/fpc.0b013e32830b0c5e
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发表时间：
2008-10-01
影响因子：
2.6
通讯作者：
Yokoi, Tsuyoshi
中科院分区：
文献类型：
--
作者：
Fukami, Tatsuki;Nakajima, Miki;Yokoi, Tsuyoshi
目的人羧酸酯酶（carboxylesterase，CES）1A 1基因（14个外显子）和CES 1A 3假基因（6个外显子）是与参考序列（NT_010498）反向重复的基因。相反，早期的研究报道了CES 1A 2基因（14个外显子）而不是CES 1A 3假基因。CES 1A 2基因内含子1下游和上游的序列分别与CES 1A 1和CES 1A 3基因的序列相同。最近已经鉴定了CES 1A 1变体，其外显子1与CES 1A 3基因的外显子1转换（转录物是CES 1A 2）。方法对55例肝组织和318例血标本（104例白种人，107例非裔美国人和107例日本人）进行CES 1A 1、CES 1A 2和CES 1A 3基因结构分析。采用实时荧光定量RT-PCR和Western blot方法检测人肝微粒体和胞液中咪达普利水解酶的活性。结果通过PCR分析，我们发现CES 1A 2基因是CES 1A 3基因的变异体。证明了四种单倍型，A（CES 1A 1野生型和CES 1A 3）、B（CES 1A 1野生型和CES 1A 2）、C（CES 1A 1变体和CES 1A 3）和D（CES 1A 1变体和CES 1A 2）。在CES 1A 1变体（白人和非洲裔美国人为17.3%，日本人为25.2%）和CES 1A 2基因（白人为14.4%，非洲裔美国人为5.1%，日本人为31.3%）的等位基因频率中观察到种族差异。在二倍体型为A/A和C/C或C/D的人肝脏中，分别未检测到CES 1A 2和CES 1A 1 mRNA。在其他参与者中，CES 1A 1 mRNA水平高于CES 1A 2 mRNA水平。从CES 1A 1 mRNA和CES 1A 2 mRNA翻译的CES 1A蛋白在人肝微粒体和胞浆组分中均被检测到，这表明编码信号肽的外显子1的差异不影响亚细胞定位。结论CES 1A 2基因是CES 1A 3假基因的变异体。本文的研究结果显著增加了我们对人类CES 1A基因结构和表达特性的理解。
Objective Human carboxylesterase (CES) 1A1 gene (14 exons) and CES1A3 pseudogene (six exons) are inverted and duplicated genes in a reference sequence (NT_010498). In contrast, earlier studies reported the CES1A2 gene (14 exons) instead of the CES1A3 pseudogene. The sequences of the CES1A2 gene downstream and upstream of intron 1 are identical with those of the CES1A1 and CES1A3 genes, respectively. A CES1A1 variant of which exon 1 is converted with that of the CES1A3 gene (the transcript is CES1A2) has recently been identified. We sought to clarify the confusing gene structure of human CES1A.Methods A panel of 55 human liver as well as 318 blood samples (104 Caucasians, 107 African-Americans, and 107 Japanese) was used to clarify the gene structures of CES1A1, CES1A2 and CES1A3. Real-time reverse transcription-PCR and western blot analysis were carried out Imidapril hydrolase activity in human liver microsomes and cytosol was determined by liquid chromatography-mass spectrometry (LC-MS)/MS.Results By PCR analyses, we found that the CES1A2 gene is a variant of the CES1A3 gene. Four haplotypes, A (CES1A1 wild type and CES1A3), B (CES1A1 wild type and CES1A2), C (CES1A1 variant and CES1A3), and D (CES1A1 variant and CES1A2), were demonstrated. Ethnic differences were observed in allele frequencies of CES1A1 variant (17.3% in Caucasians and African-Americans and 25.2% in Japanese) and CES1A2 gene (14.4% in Caucasians, 5.1% in African-Americans, and 31.3% in Japanese). In human livers whose diplotype was A/A and C/C or C/D, no CES1A2 and CES1A1 mRNA was detected, respectively. In the other participants, the CES1A1 mRNA levels were higher than the CES1A2 mRNA levels. The CES1A proteins translated from CES1A1 mRNA and CES1A2 mRNA were detected in both human liver microsomes and cytosol fractions suggesting that the differences in exon 1 encoding a signal peptide did not affect the subcellular localization. Imidapril hydrolase activities reflected the CES1A protein levels.Conclusion We found that the CES1A2 gene is a variant of the CES1A3 pseudogene. The findings presented here significantly increase our understanding about the gene structure and expression properties of human CES1A.