The gene for human protein Z is localized to chromosome 13 at band q34 and is coded by eight regular exons and one alternative exon.
The gene for human protein Z is localized to chromosome 13 at band q34 and is coded by eight regular exons and one alternative exon.
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人类 Z 蛋白基因位于 13 号染色体 q34 条带，由 8 个常规外显子和 1 个替代外显子编码。
作者：
K. Fujimaki;T. Yamazaki;Masafumi Taniwaki;Akitada Ichinose
人蛋白Z是一种维生素K依赖性血浆糖蛋白，缺乏它会导致轻度出血倾向。蛋白Z似乎通过结合凝血酶并促进其与磷脂囊泡的结合来帮助止血。在这项研究中，表征蛋白Z的基因，其组织和结构的白细胞DNA的PCR扩增和分离的噬菌体克隆从人类基因组文库的组合确定。该基因全长约14 kb，由9个外显子组成，其中包括一个选择性外显子。值得注意的是，这种基因结构与其他维生素K依赖性蛋白质（如因子VII、IX和X以及蛋白质C）的基因结构基本相同。8个常规外显子的外显子/内含子边界的内含子中的核苷酸是共有的GT-AG序列。相比之下，在一个可选的外显子/内含子交界处的序列被发现是GC，而不是GT。额外的外显子插入一个独特的肽组成的22个氨基酸的prepro前导序列。以前在因子VII中观察到类似的情况，但在其他维生素K依赖性血浆蛋白中没有观察到。我们还通过PCR扩增人/仓鼠细胞杂种的基因组DNA，将蛋白Z基因分配到13号染色体。荧光原位杂交，采用基因组克隆编码人类蛋白Z，进一步本地化的基因带q34，其中其他三个维生素K依赖性蛋白质的基因聚集。这些基因可能是通过在该位点复制祖先基因而进化的。
Human protein Z is a vitamin K-dependent plasma glycoprotein, deficiency of which leads to a mild bleeding tendency. Protein Z appears to assist hemostasis by binding thrombin and promoting its association with phospholipid vesicles. In this study, to characterize the gene for protein Z, its organization and structure were determined by a combination of PCR amplification of leukocyte DNA and isolation of phage clones from a human genomic library. The gene spanned about 14 kb and consisted of 9 exons including one alternative exon. It was of note that the gene organization was essentially identical to that of other vitamin K-dependent proteins, such as factors VII, IX, and X and protein C. The nucleotides in introns at exon/intron boundaries for eight regular exons were the consensus GT-AG sequences. In contrast, the sequence at an optional exon/intron junction was found to be GC rather than GT. The extra exon inserts a unique peptide consisting of 22 amino acids in the prepro-leader sequence. A similar situation was previously observed in factor VII, but not in other vitamin K-dependent plasma proteins. We also assigned the gene for protein Z to chromosome 13 by PCR amplification of genomic DNAs from human/hamster cell hybrids. Fluorescence in situ hybridization, employing a genomic clone coding for human protein Z, further localized the gene to band q34, where the genes of three other vitamin K-dependent proteins are clustered. These genes may have evolved via duplication of an ancestral gene at this locus.