Cotrim P C, Paranhos-Baccala G, Santos M R, Mortensen C, Cano M I, Jolivet M, Camargo M E, Mortara R A, Da Silveira J F
Department of Microbiology, Immunology and Parasitology, Escola Paulista de Medicina, São Paulo, Brazil.
Mol Biochem Parasitol. 1995 Apr;71(1):89-98. doi: 10.1016/0166-6851(95)00036-z.
We have studied the genomic organization and expression of the gene encoding a high molecular mass (300 kDa) repetitive antigen associated with the cytoskeleton of Trypanosoma cruzi. Protease digestion of the native protein, restriction analysis of genomic DNA and sequencing of genomic and cDNA clones indicated that most of the protein is built up by tandemly arranged, nearly identical repeats of 68 amino acids. The gene size was estimated to be approx. 9.4 kb based on the sizes of the transcript and the native protein. The nucleotide sequence conservation among the repeats indicates that selective sequence homogenization, presumably through gene conversion, maintained the amino-acid sequence conservation. Two duplicated allelic forms of this gene were mapped in fragments of about 20 kb. In some strains an additional allele was located in a fragment of 9.4 kb. Our results suggest that this repetitive antigen is a structural protein which could be involved in the attachment of the flagellum to the cell body.
我们研究了编码与克氏锥虫细胞骨架相关的高分子量（300 kDa）重复抗原的基因的基因组组织和表达。对天然蛋白质进行蛋白酶消化、对基因组DNA进行限制性分析以及对基因组和cDNA克隆进行测序表明，该蛋白质的大部分由68个氨基酸的串联排列、几乎相同的重复序列组成。根据转录本和天然蛋白质的大小，估计该基因大小约为9.4 kb。重复序列之间的核苷酸序列保守性表明，可能通过基因转换的选择性序列均一化维持了氨基酸序列的保守性。该基因的两种重复等位基因形式定位于约20 kb的片段中。在一些菌株中，另一个等位基因位于9.4 kb的片段中。我们的结果表明，这种重复抗原是一种结构蛋白，可能参与鞭毛与细胞体的附着。
