An analysis of cosmid clones of nuclear DNA from Trypanosoma brucei shows that the genes for variant surface glycoproteins are clustered in the genome.
An analysis of cosmid clones of nuclear DNA from Trypanosoma brucei shows that the genes for variant surface glycoproteins are clustered in the genome.
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对布氏锥虫核 DNA 粘粒克隆的分析表明，变异表面糖蛋白的基因聚集在基因组中。
DOI：
10.1093/nar/10.19.5905
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发表时间：
1982
影响因子：
14.9
通讯作者：
F. Grosveld
中科院分区：
文献类型：
--
作者：
L. Ploeg;D. Valerio;T. Lange;A. Bernards;P. Borst;F. Grosveld
布氏锥虫含有一百多个编码不同变异表面糖蛋白（VSG）的基因。这些基因中的一些的激活涉及基因的复制（基本拷贝或BC）和复制物转座到表达位点（产生表达连锁拷贝或ELC）。我们已经在大肠杆菌的粘粒载体中克隆了基因组DNA的大片段。含有基因117、118和121的BC的粘粒很容易获得，但含有ELC的DNA在所用的粘粒和质粒克隆系统中被强烈选择。我们已经分析了VSG基因在基因组中的分布，使用探针的序列在边缘的转座片段，其中部分同源的这些基因。在基因组粘粒克隆库中，约9%的菌落与来自转座片段的5 '和3'边缘的探针杂交，表明这些序列在基因组中是连锁的。此外，117和118 BC cosmetics包含几个额外的推定串联VSG基因，从杂交和序列分析推断。我们的结论是，VSG基因是高度聚集的，并在转座片段的边界共享共同的序列。
Trypanosoma brucei contains more than a hundred genes coding for the different variant surface glycoproteins (VSGs). Activation of some of these genes involves the duplication of the gene (the basic copy or BC) and transposition of the duplicate to an expression site (yielding the expression-linked copy or ELC). We have cloned large fragments of genomic DNA in cosmid vectors in Escherichia coli. Cosmids containing the BCs of genes 117, 118 and 121 were readily obtained, but DNA containing the ELCs was strongly selected against in the cosmid and plasmid cloning systems used. We have analysed the distribution of VSG genes in the genome using probes for the sequences at the edges of the transposed segment which are partially homologous among these genes. In genomic cosmid clone banks, about 9% of all colonies hybridize with probes from the 5'- and 3'-edges of the transposed segment, showing that these sequences are linked in the genome. Moreover, the 117 and 118 BC cosmids contain several additional putative VSG genes in tandem, as deduced from hybridization and sequence analyses. We conclude that the VSG genes are highly clustered and share common sequences at the borders of the transposed segment.