Two genes encoding unique proliferating-cell-nuclear-antigens are expressed in Toxoplasma gondii
Two genes encoding unique proliferating-cell-nuclear-antigens are expressed in Toxoplasma gondii
复制标题
DOI：
10.1016/s0166-6851(00)00240-1
复制
发表时间：
2000-07-01
影响因子：
1.5
通讯作者：
White, MW
中科院分区：
文献类型：
--
作者：
Guerini, MN;Que, XC;White, MW
从弓形虫速殖子cDNA文库中克隆了两个新的增殖细胞核抗原基因（TgPCNA 1和TgPCNA 2）的cDNA序列，用cDNA探针进行Southern杂交，证实了两个PCNA基因在弓形虫速殖子中的存在。弓形虫基因组DNA在T.从恶性疟原虫12和13号染色体获得的序列数据中发现了与每个TgPCNA cDNA和密切相关的PCNA编码区（命名为PfPCNA 1和PfPCNA 2）匹配的gondii数据库。发现与TgPCNA 2和PfPCNA 2（37%同一性）相比，TgPCNA 1和PfPCNA 1共享49%的最高氨基酸同一性，而种内PCNA被确定为不太相似（27-30%同一性）。系统发育分析表明，这两个apicomplexan PCNAs是这些寄生虫的共同祖先的基因重复的结果。特异于TgPCNA 1（类似于40 kDa）或TgPCNA 2（类似于37 kDa）的抗体在速殖子提取物中检测到单一抗原种类，这些抗原种类在代表T.弓形虫I型、II型和III型菌株。TgPCNA 1特异性cDNA探针在北方印迹上检测到多个mRNA种类，当组合时，其表达比TgPCNA 2探针检测到的单个mRNA种类高5-7倍。mRNA种类的数量和比较mRNA水平的差异表明每个TgPCNA基因是独立控制的，尽管鉴于几乎相等的蛋白质水平，转录后机制可能负责均衡蛋白质表达。(C)2000 Elsevier Science B. V.保留所有权利。
Complete cDNA sequences encoding two novel proliferating-cell-nuclear-antigens (designated TgPCNA1 and 2) were isolated fi om a Toxoplasma gondii tachyzoite cDNA library, and Southern analysis using cDNA probes confirmed the presence of two PCNA genes in T. gondii genomic DNA. Expressed-sequence-tags were identified in the T. gondii database that matched each TgPCNA cDNA and closely related PCNA coding regions (designated PfPCNA1 and 2) were discovered in sequence data obtained from chromosome 12 and 13 of Plasmodium falciparum. TgPCNA1 and PfPCNA1 were found to share the highest amino acid identity at 49% compared to TgPCNA2 and PfPCNA2 (37% identity) whereas intraspecies PCNAs were determined to be less similar (27-30% identity). Phylogenetic analysis suggests the two apicomplexan PCNAs are the result of a gene duplication in the common ancestor of these parasites. Antibodies specific for TgPCNA1 (similar to 40 kDa) or TgPCNA2 (similar to 37 kDa) detected single antigen species in tachyzoite extracts that were expressed at similar levels in isolates representative of the T. gondii Type I, II and III strains. TgPCNA1-specific cDNA probes detected multiple mRNA species on Northern blots, which when combined, were expressed 5-7 fold higher than the single species of mRNA detected by the TgPCNA2 probe. The difference in the number of mRNA species and comparative mRNA levels suggests each TgPCNA gene is independently controlled, although in light of the nearly equal levels of protein a post-transcriptional mechanism may be responsible for equalizing protein expression. (C) 2000 Elsevier Science B.V. All rights reserved.