Mottram J C, Smith G
Wellcome Unit of Molecular Parasitology, University of Glasgow, UK.
Gene. 1995 Aug 30;162(1):147-52. doi: 10.1016/0378-1119(95)00350-f.
The cyclin-dependent kinases, most notable of which is cdc2, are key regulators of the cell cycle, and are highly conserved in evolution. We have cloned and analysed three cdc2-related kinase-encoding genes (tbcrk1-3) from the protozoan parasite Trypanosoma brucei. tbcrk1 encodes a 34-kDa protein with 54% amino acid (aa) identity to the human cdc2, tbcrk2 a 39-kDa protein with 49% identity and tbcrk3 a 35-kDa protein with 54% identity. tbcrk1-3 have substitutions in the 16-aa sequence, the 'PSTAIRE' domain, that characterises the cdc2-related kinase family, to give PCTAIRE, PSTAVRE and PQTALRE motifs, respectively. The three kinases have conserved Tyr and Thr residues that are sites of phosphorylation in cdc2 and are important for regulating kinase activity. Southern blot analysis revealed that each tbcrk is a single copy gene. Pulse-field electrophoresis located the tbcrk genes to some of the largest of the trypanosome chromosomes at greater than 3 Mb. Western blots with anti-PSTAIRE polyclonal antibody detected proteins of 32, 43 and 65 kDa in all life-cycle stages and a 90-kDa protein in bloodstreams forms, implying the presence of a family of cdc2-related kinases. Trypanosomes have a remarkably large gene family of cdc2-related kinases for such a primitive organism. The crk genes may be involved in controlling aspects of the cell cycle which are linked to the differentiation of the parasite during its complex life cycle.
细胞周期蛋白依赖性激酶（其中最著名的是cdc2）是细胞周期的关键调节因子，在进化过程中高度保守。我们从原生动物寄生虫布氏锥虫中克隆并分析了三个与cdc2相关的激酶编码基因（tbcrk1 - 3）。tbcrk1编码一种34 kDa的蛋白质，与人类cdc2的氨基酸（aa）同一性为54%，tbcrk2编码一种39 kDa的蛋白质，同一性为49%，tbcrk3编码一种35 kDa的蛋白质，同一性为54%。tbcrk1 - 3在16个氨基酸序列（即“PSTAIRE”结构域）中存在取代，该结构域是cdc2相关激酶家族的特征，分别产生PCTAIRE、PSTAVRE和PQTALRE基序。这三种激酶具有保守的酪氨酸和苏氨酸残基，它们是cdc2中的磷酸化位点，对调节激酶活性很重要。Southern印迹分析表明每个tbcrk都是单拷贝基因。脉冲场电泳将tbcrk基因定位到锥虫一些大于3 Mb的最大染色体上。用抗PSTAIRE多克隆抗体进行的Western印迹在所有生命周期阶段检测到32、43和65 kDa的蛋白质，在血流形式中检测到90 kDa的蛋白质，这意味着存在一个cdc2相关激酶家族。对于这样一种原始生物，锥虫拥有一个非常大的cdc2相关激酶基因家族。crk基因可能参与控制细胞周期中与寄生虫在其复杂生命周期中的分化相关的方面。
