Complete sequence of a cDNA clone specifying sandbar shark immunoglobulin light chain: gene organization and implications for the evolution of light chains.
Complete sequence of a cDNA clone specifying sandbar shark immunoglobulin light chain: gene organization and implications for the evolution of light chains.
复制标题
指定沙洲鲨免疫球蛋白轻链的 cDNA 克隆的完整序列：基因组织和对轻链进化的影响。
DOI：
10.1073/pnas.89.1.276
复制
发表时间：
1992
影响因子：
11.1
通讯作者：
Marchalonis,JJ
中科院分区：
文献类型：
--
作者：
Hohman,VS;Schluter,SF;Marchalonis,JJ
分离并测序了沙洲鲨免疫球蛋白轻链全长cDNA克隆。通过与人类lambda链的比对，可以清楚地识别出鲨鱼轻链中的先导区、框架区、互补性决定区、连接区和恒定区。在可变区和恒定区，人类和鲨鱼的序列大约有40-50%相同。我们对各个片段进行了序列比较，并为可变区域构建了系统发育树。这些研究将鲨鱼蛋白鉴定为lambda链。此外，沙洲鲨的轻链与角鲨（Heterodontus francisci）的轻链只有较远的亲缘关系[Shamblott， M. J. & Litman， G. W. (1989) Proc. Natl。学会科学。（USA 86, 4684-4688），表明鲨鱼物种之间的长时间进化分化导致了序列上的实质性差异的产生。绘制了14个基因组克隆中可变、连接和恒定基因片段的位置。这些片段以单独的簇（可变的、连接的、恒定的）连接在一起，占用3-7千碱基。根据单个克隆中基因之间的间距，群集排列可分为两种模式。这种排列与在高等脊椎动物中观察到的根本不同。
A full-length cDNA clone specifying sandbar shark (Carcharhinus plumbeus) immunoglobulin light chain has been isolated and sequenced. By alignment with human lambda chains, the leader, framework, complementarity-determining, joining, and constant regions are clearly identified in the shark light chain. Approximately 40-50% identity is shared between the human and shark sequences in the variable and constant regions. We have performed sequence comparisons of the individual segments and constructed phylogenetic trees for the variable region. These studies identify the shark protein as a lambda chain. In addition, the sandbar shark light chain is only distantly related to that of horned shark (Heterodontus francisci) [Shamblott, M. J. & Litman, G. W. (1989) Proc. Natl. Acad. Sci. USA 86, 4684-4688], demonstrating that the long evolutionary time of divergence among shark species has led to the generation of substantial differences in sequence. The positions of the variable, joining, and constant gene segments in 14 genomic clones have been mapped. The segments are linked in individual clusters (variable, joining, constant) occupying 3-7 kilobases. Cluster arrangement can be grouped into two patterns based upon spacing between the genes in the individual clones. This arrangement is fundamentally different from that observed in higher vertebrates.