STRUCTURE OF THE CHICKEN GENE FOR SNAP-25 REVEALS DUPLICATED EXONS ENCODING DISTINCT ISOFORMS OF THE PROTEIN
STRUCTURE OF THE CHICKEN GENE FOR SNAP-25 REVEALS DUPLICATED EXONS ENCODING DISTINCT ISOFORMS OF THE PROTEIN
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DOI：
10.1006/jmbi.1993.1485
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发表时间：
1993-09-05
影响因子：
5.6
通讯作者：
BARK, IC
中科院分区：
文献类型：
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作者：
BARK, IC
SNAP-25（突触体相关蛋白25 kDa）是一种神经元特异性但不均匀表达的蛋白。SNAP-25蛋白的表达与突触发生的时间有关，主要存在于突触前区。本文报道了鸡SNAP-25基因的克隆和鉴定。该基因跨越超过65kb的基因组DNA，被打断成9个不同的外显子。对mRNA 5 '端的鉴定表明，转录起始位点是异质的，尽管主要的转录起始位点存在于假定的TATA-box下游30 bp处。外显子-内含子组织分析表明，外显子5存在于两个同源但不同的版本，相隔140个碱基对。两个外显子5都表达为mRNA，表明选择性剪接调节SNAP-25蛋白的两个同工异构体a和b的表达。选择性剪接导致蛋白质之间的9个氨基酸残基的差异在一个区域被证明是受棕榈酰化。这表明这两种异构体在被脂肪酰化修饰的能力或效率上存在差异，表明它们与神经元膜相互作用的能力存在差异。
SNAP-25 (synaptosomal associated protein of 25 kDa) is a neuronal-specific but non-uniformly expressed protein. Expression is correlated to the time of synaptogenesis and SNAP-25 protein is found predominantly in presynaptic fields. Here we report the cloning and characterization of the SNAP-25 chicken gene. The gene spans more than 65 kb of genomic DNA and is interrupted into nine different exons. Identification of the 5′-end of the mRNA showed that transcriptional initiation is heterogeneous, although a major transcriptional start site is present 30 bp downstream of a putative TATA-box. Analysis of the exon-intron organization revealed that exon 5 exists in two homologous but distinct versions separated by 140 base-pairs. Both exons 5 are expressed as mRNA, indicating that alternative splicing regulates the expression of two isoforms, a and b, of the SNAP-25 protein. The alternative splicing results in a difference of nine amino acid residues between the proteins in a domain demonstrated to be subject to palmitoylation. This implies that the two isoforms differ in their capacity or efficiency to be modified by fatty acylation, suggesting divergent abilities to interact with neuronal membranes.