Structure of the rabbit cytochrome P450IIC3 gene, a constitutive member of the P450IIC subfamily.
Structure of the rabbit cytochrome P450IIC3 gene, a constitutive member of the P450IIC subfamily.
复制标题
兔细胞色素 P450IIC3 基因的结构，P450IIC 亚家族的组成成员。
DOI：
10.1021/bi00467a021
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发表时间：
1990
期刊：
影响因子：
2.9
通讯作者：
Kemper,B
中科院分区：
文献类型：
--
作者：
Chan,G;Kemper,B
ching Chan§和Byron Kemper*伊利诺伊大学厄巴纳-香槟分校生理与生物物理系，美国伊利诺斯州厄巴纳61801摘要：兔细胞色素P450IIC3基因片段已克隆成功。细胞色素P450IIC3是细胞色素P450IIC亚家族的组成成员，该亚家族包含组成基因和苯巴比妥反应基因。细胞色素P450IIC3基因长度至少为25kbp，包含8个内含子，这些内含子具有5‘GT ’和3'AG '，与其他家族ii基因位于相同的位置。5'侧翼区域包含一个一致的TATA位点，距离RNA起始位点约25 bp，通过引物延伸法绘制。其他潜在的调控序列包括CCA AT序列和与肝脏特异性因子HNF-1和一般转录因子AP-1和oct结合位点相似的序列。该基因序列与细胞色素P450IIC3克隆的cDNA序列在1400个核苷酸中只有2个不同，其中1个导致氨基酸变化。由于克隆的细胞色素P450IIC3 cDNA中不存在编码外显子1和部分外显子2的序列，因此通过聚合酶链反应扩增了cDNA 5'端的475个核苷酸片段，并进行了克隆和测序。该cDNA序列与该基因外显子序列一致。从该基因获得的蛋白质序列与直接确定的蛋白质序列有9个位置不同。通过外显子与其他细胞色素P450IIC蛋白的氨基酸序列比较发现，一般来说，c端外显子的相似性大于n端外显子。这种趋势在与P450IIC4/5的比较中被夸大了，P450IIC4/5的外显子8具有87%的高相似性，而整体为65%，外显子6为58%。然而，不导致氨基酸变化的核苷酸差异在外显子5和外显子8上相似，这表明基因转换不是导致这两个外显子之间相似性差异的原因，并表明该区域蛋白质序列的保守可能很重要。
Ging Chan § and Byron Kemper* Department of Physiology and Biophysics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 Received September 29, 1989; Revised Manuscript Received December 19, 1989 abstract: Fragments of rabbit DNA have been clonedwhich encompass the gene for rabbit cytochrome P450IIC3. Cytochrome P450IIC3 is a constitutive member of the cytochrome P450IIC subfamily which contains both constitutive and phenobarbital-responsive genes. The cytochrome P450IIC3 gene spans at least 25 kbp and contains 8 introns which have 5'GT’s and 3'AG’s and are located in the same positions as in other familyII genes. The 5'flanking region contains a consensus TATA site about 25 bp from the RNA initiation site which was mapped by the primer extension method. Other potential regulatory sequences include a CCA AT sequence and sequences similar to binding sites for the liver-specificfactor HNF-1 and the general transcription factors AP-1 and OCT. The gene sequence differs from the cytochrome P450IIC3 cloned cDNA sequence in only 2 of 1400 nucleotides, 1 of which results in an amino acid change. Since sequences coding for exon 1 and part of exon 2 were not present in the cloned cytochrome P450IIC3 cDNA, a 475-nucleotide fragment of the 5'end of the cDNA was amplified by the polymerase chain reaction, cloned, and sequenced. The sequence of this cDNA was identical with the gene exon sequence. The protein sequence derived from the gene differs in nine positions from that determined directly for the protein. A comparison of the amino acid sequence by exons with other cytochrome P450IIC proteins revealed that, in general, the similarity was greater in C-terminal exons than in N-terminal ones. This trend is exaggerated in the comparison with P450IIC4/5, for which exon 8 had a high similarity of 87% compared to 65% overall and 58% for exon 6. However, divergence of nucleotides that do not result in amino acid changes was similar in exon 5 and exon 8, indicating that gene conversion was not responsible for the difference in similarity between these two exons and suggesting that conservation of protein sequence in this region may be important.