Tsuchiya Y, Uyeda K
Research Service, Department of Veterans Affairs Medical Center, Dallas, Texas.
Arch Biochem Biophys. 1994 May 1;310(2):467-74. doi: 10.1006/abbi.1994.1194.
Previously we described the coding region of bovine heart Fructose 6-P,2-kinase:Fructose 2,6-bisphosphatase as determined from cDNA. We have isolated several overlapping clones and determined the DNAs which encode the entire mRNA of bovine heart bifunctional enzyme, including the 5'- and 3'-noncoding regions. the exon-intron structure of the 27-kb gene was determined and shown to consist of 16 exons. There are one primary and two secondary transcription initiation sites with the coding region beginning at exon 2. Exons 3-7 encode the Fructose 6-P,2-kinase domain, and exons 9-14 encode the Fructose 2,6-biphosphatase domain. Exon 15 is a unique exon for the heart type isozyme and contains the phosphorylation sites for protein kinases A and C. Alternative splicing of this exon accounts for the expression of two heart type isozymes in cardiac muscle. Exon 16 (also unique), 1820 bp long and located 7 kb downstream of exon 15, encodes the short C-terminus of the enzyme and is completely different from that of the rat heart bifunctional enzyme gene.
此前我们已根据cDNA确定了牛心果糖6-磷酸，2-激酶：果糖2,6-二磷酸酶的编码区。我们分离出了几个重叠克隆，并确定了编码牛心双功能酶完整mRNA的DNA，包括5'-和3'-非编码区。确定了27kb基因的外显子-内含子结构，显示其由16个外显子组成。有一个主要转录起始位点和两个次要转录起始位点，编码区从外显子2开始。外显子3-7编码果糖6-磷酸，2-激酶结构域，外显子9-14编码果糖2,6-二磷酸酶结构域。外显子15是心脏型同工酶特有的外显子，包含蛋白激酶A和C的磷酸化位点。该外显子的可变剪接导致心肌中两种心脏型同工酶的表达。外显子16（也是独特的），长1820bp，位于外显子15下游7kb处，编码该酶的短C末端，与大鼠心脏双功能酶基因的C末端完全不同。
