TRYPANOSOMES OF SUBGENUS TRYPANOZOON ARE DIPLOID FOR HOUSEKEEPING GENES
TRYPANOSOMES OF SUBGENUS TRYPANOZOON ARE DIPLOID FOR HOUSEKEEPING GENES
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DOI：
10.1016/0166-6851(85)90066-0
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发表时间：
1985-01-01
影响因子：
1.5
通讯作者：
BORST, P
中科院分区：
文献类型：
--
作者：
GIBSON, WC;OSINGA, KA;BORST, P
到目前为止，锥虫的倍性仍未确定，尽管同工酶研究和DNA含量和复杂性的直接测量表明是二倍体。直接的细胞遗传学分析是不可能的，因为染色体在细胞周期的任何阶段都不会凝聚。我们现在通过对三种糖酵解酶基因(磷酸甘油酸激酶、丙糖磷酸异构酶、甘油醛磷酸脱氢酶)和微管蛋白基因簇及其周围酶切位点的分析，证明锥虫亚属的锥虫是这些看家基因的二倍体。这一结果仍然与锥虫变异表面糖蛋白(VSG)基因的单拷贝性质相一致，如果不同的VSG基因存在于配对染色体上的相应位置。利用脉冲场梯度凝胶电泳法，我们发现这三种糖酵解酶的基因都位于非常大的DNA分子中，但磷酸丙糖异构酶的基因与其他两种酶的基因是不同的。由于这三种酶都位于锥虫微体糖体中，所以糖体酶的基因并不都聚集在锥虫基因组的一个染色体片段中。
The ploidy of trypanosomes has until now remained undetermined, although isoenzyme studies and direct measurements of DNA content and complexity suggest diploidy. Direct cytogenetic analysis is not possible, because the chromosomes do not condensate at any stage of the cell cycle. We now present evidence from analysis of restriction site polymorphisms in and around three glycolytic enzyme genes (phosphoglycerate kinase, triosephosphate isomerase, glyceraldehyde phosphate dehydrogenase) and the tubulin gene cluster, that trypanosomes of subgenus Trypanozoon are diploid for these housekeeping genes. This result is still compatible with the single copy nature of variant surface glycoprotein (VSG) genes in Trypanozoon, if different VSG genes are present in corresponding positions on paired chromosomes. Using pulse field gradient gel electrophoresis, we show that the genes for the three glycolytic enzymes are all located in very large DNA molecules, but the gene for triosephosphate isomerase is in another fraction from the genes for the other two enzymes. Since all three enzymes are located in glycosomes, which are trypanosome microbodies, the genes for glycosomal enzymes are not all clustered in one chromosomal segment of the trypanosome genome.