ISOLATION OF A SHARK IMMUNOGLOBULIN LIGHT-CHAIN CDNA CLONE ENCODING A PROTEIN RESEMBLING MAMMALIAN KAPPA-LIGHT CHAINS - IMPLICATIONS FOR THE EVOLUTION OF LIGHT-CHAINS
ISOLATION OF A SHARK IMMUNOGLOBULIN LIGHT-CHAIN CDNA CLONE ENCODING A PROTEIN RESEMBLING MAMMALIAN KAPPA-LIGHT CHAINS - IMPLICATIONS FOR THE EVOLUTION OF LIGHT-CHAINS
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DOI：
10.1073/pnas.90.22.10603
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发表时间：
1993-11-15
影响因子：
11.1
通讯作者：
FLAJNIK, MF
中科院分区：
文献类型：
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作者：
GREENBERG, AS;STEINER, L;FLAJNIK, MF
免疫球蛋白kappa和lambda轻链(L)在进化中出现的时间尚不清楚。从软骨鱼类护士鲨(Ginglymostoma Cirratum)中分离到一个L链基因克隆，其可变区氨基酸序列与哺乳动物V(Kappa)区的同源性高达60%。基因组分析表明，该L链基因座为簇型基因结构，类似于鲨鱼类免疫球蛋白L链基因座，而不是哺乳动物的kappa基因座。我们推测，祖先L链的同型分化可能发生在4亿-4.5亿年前弹鳃动物出现之前。鲨鱼两种同工型之间基因组织的相似性可能反映了祖先L链所利用的基因组织。
The time of emergence of immunoglobulin kappa and lambda light (L) chains in evolution is unknown. An L chain cDNA clone was isolated from the nurse shark (Ginglymostoma cirratum), a cartilaginous fish, whose predicted variable (V) region amino acid sequence has up to 60% sequence identity to mammalian V(kappa) domains. Genomic analyses suggest a cluster-type gene organization for this L chain locus, similar to the shark lambda-like immunoglobulin L chain loci rather than mammalian kappa loci. We propose that divergence of the ancestral L chain into isotypes likely occurred before the emergence of elasmobranchs 400-450 million years ago. Similarities in gene organization between the two isotypes in sharks may reflect the gene organization utilized by the ancestral L chain.