Structure and pre‐B lymphocyte restricted expression of the VpreB in humans and conservation of its structure in other mammalian species.
Structure and pre‐B lymphocyte restricted expression of the VpreB in humans and conservation of its structure in other mammalian species.
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人类中 VpreB 的结构和前 B 淋巴细胞表达及其在其他哺乳动物物种中的结构保守性受到限制。
作者：
S. Bauer;A. Kudo;F. Melchers
发现包括人类在内的几种哺乳动物的 DNA 含有一个或多个限制性酶消化的 DNA 片段，这些片段在严格条件下与小鼠 VpreB 基因杂交，显示出至少 70% 的核苷酸序列同源性，表明 VpreB 基因座可能在哺乳动物中广泛存在且高度保守。分离并测序了人 VpreB 基因组克隆。两个外显子和插入的内含子的间隔几乎与小鼠 VpreB1 基因中的相同，并且与小鼠基因具有 76% 的序列同源性。与小鼠 VpreB1 基因一样，人类 VpreB 基因的 5' 端包含 Ig 结构域的特征，而 3' 端与 Ig 无关。因此，VpreB 基因的这种 3′ Ig 非相关结构可能在 6500 万年前的人类和小鼠物种形成之前就已经存在。编码整个假定的第二框架区和第三框架区的一段序列在人和小鼠 VpreB 中是相同的。人类 VpreB 基因似乎在人类前 B 细胞系中选择性表达为 0.85 kb poly(A)+ RNA。它的表达有望成为检测正常和恶性人类前 B 淋巴细胞的有用标记。
DNA from several mammals, including humans, was found to contain one or more restriction enzyme digested DNA fragments which hybridized to the mouse VpreB gene under stringencies demonstrating at least 70% nucleotide sequence homologies, indicating that the VpreB locus may be widespread and highly conserved among mammals. A human VpreB genomic clone was isolated and sequenced. Two exons and the intervening intron are spaced almost identically as in the mouse VpreB1 gene, and show 76% sequence homology to the mouse gene. As in the mouse VpreB1 gene, the 5′ end of the human VpreB gene contains characteristic features of Ig domains, while the 3′ end is Ig non‐related. This 3′ Ig non‐related structure of the VpreB gene(s) may, therefore, have existed before the speciation of humans and mice over 65 million years ago. Sequences encoding the entire putative second framework region and a stretch in the third framework region are identical in human and mouse VpreB. the human VpreB gene appears to be selectively expressed in human pre‐B cell lines as an 0.85 kb poly(A)+ RNA. Its expression promises to be a useful marker for the detection of normal and malignant human pre‐B lymphocytes.