Rat cystathionine beta-synthase. Gene organization and alternative splicing.
Rat cystathionine beta-synthase. Gene organization and alternative splicing.
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DOI：
10.1016/s0021-9258(19)49931-6
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发表时间：
1992-06
期刊：
影响因子：
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通讯作者：
M. Swaroop;K. Bradley;T. Ohura;T. Tahara;M. Roper;L. Rosenberg;J. Kraus
中科院分区：
文献类型：
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作者：
M. Swaroop;K. Bradley;T. Ohura;T. Tahara;M. Roper;L. Rosenberg;J. Kraus
我们阐明了大鼠胱硫醚β-合酶基因的结构和选择性剪接模式。该基因长度为20-25个内切酶对，其编码区分为17个外显子。这些是可变剪接的，形成四种不同的mRNA（I型至IV型）。预测的开放阅读框分别编码61.5、39、60和52.5 kDa的蛋白质。外显子13和16交替使用且相互排斥。外显子13包括一个终止密码子，编码II型和IV型中发现的独特羧基末端序列。外显子16仅存在于I型中。I型和III型，其相差42个核苷酸（外显子16），是大鼠肝脏中主要的合酶mRNA形式。17精氨酸肽从纯肝合酶匹配推导的氨基酸序列的I型和III型。这两种多肽在肝脏提取物中可检测到;当在转染的中国仓鼠细胞中表达时，每种多肽均表现出酶活性。合成酶显示与来自低等生物的吡哆醛5 '-磷酸依赖性酶的实质性序列相似性。与大肠杆菌O-乙酰丝氨酸（巯基）裂解酶（cysK）的相似性为52%;大肠杆菌色氨酸合成酶β链（trpB），36%;酵母丝氨酸脱氨酶，33%。合成酶中的赖氨酸116与这些酶的已建立的吡啶氧基赖氨酸残基对齐，表明它是吡哆醛5 '-磷酸结合残基。
We elucidated the structure and alternative splicing patterns of the rat cystathionine beta-synthase gene. The gene is 20-25 kilobase pairs long, and its coding region is divided into 17 exons. These are alternatively spliced, forming four distinct mRNAs (types I through IV). The predicted open reading frames encode proteins of 61.5, 39, 60, and 52.5 kDa, respectively. Exons 13 and 16 are used alternatively and mutually exclusively. Exon 13 includes a stop codon and encodes the unique carboxyl-terminal sequence found in types II and IV. Exon 16 is present only in type I. Types I and III, which differ by 42 nucleotides (exon 16), are the predominant synthase mRNA forms in rat liver. Seventeen arginine peptides from pure liver synthase matched the deduced amino acid sequences of types I and III. These two polypeptides are detectable in liver extracts; each exhibits enzymatic activity when expressed in transfected Chinese hamster cells. Synthase shows substantial sequence similarity with pyridoxal 5‘-phosphate dependent enzymes from lower organisms. Similarity of synthase to Escherichia coli O-acetylserine (thiol)-lyase (cysK) is 52%; E. coli tryptophan synthase beta chain (trpB), 36%; yeast serine deaminase, 33%. Lysine 116 in synthase aligns with the established pyridoxyllysine residue of these enzymes suggesting that it is the pyridoxal 5‘-phosphate binding residue.