Concerted evolution at a multicopy locus in the protozoan parasite Theileria parva: Extreme divergence of potential protein-coding sequences
Concerted evolution at a multicopy locus in the protozoan parasite Theileria parva: Extreme divergence of potential protein-coding sequences
复制标题
DOI：
10.1128/mcb.17.3.1666
复制
发表时间：
1997-03-01
影响因子：
5.3
通讯作者：
Gobright, E
中科院分区：
文献类型：
--
作者：
Bishop, R;Musoke, A;Gobright, E
脊椎动物中多拷贝基因家族的协同进化被认为是产生生物学新奇的重要力量，但对于原生动物的多拷贝基因尚未有记录。多拷贝基因座Tpr由串联排列的开放阅读框（ORF）组成，包含几个重复元件已被描述为小泰勒虫，本文中，我们发现来自T. parva Uganda（1,108个密码子）和Boleni（699个密码子）与同源DNA中的多拷贝序列杂交，但在14个异源T. Uganda和Boleni ORF的3 ′/C-末端分别与Tpr 1和Tpi 2重复元件具有75%的相似性和同一性。parva Muguga，Tpr 1同源序列中检测到另外两种泰勒虫。在同一株T. Tpr 1和Tpr 2的氨基酸序列包含6个预测的膜结合片段，同义与非同义替换的比例表明Tpr 1的进化类似于编码蛋白质的DNA，编码p67抗原的基因的核苷酸序列在T. parva Muguga，Boleni和Uganda，包括密码子中的第三个碱基，这些数据表明协同进化可以导致编码序列的根本分歧，这可能是产生新基因的机制。
Concerted evolution of multicopy gene families in vertebrates is recognized as an important force in the generation of biological novelty but has not been documented for the multicopy genes of protozoa, A multicopy locus, Tpr, which consists of tandemly arrayed open reading frames (ORFs) containing several repeated elements has been described for Theileria parva, Herein we show that probes derived from the 5'/N-terminal ends of ORFs in the genomic DNAs of T. parva Uganda (1,108 codons) and Boleni (699 codons) hybridized with multicopy sequences in homologous DNA but did not detect similar sequences in the DNA of 14 heterologous T. parva stocks and clones, The probe sequences were, however, protein coding according to predictive algorithms and codon usage, The 3'/C-terminal ends of the Uganda and Boleni ORFs exhibited 75% similarity and identity, respectively, to the previously identified Tpr1 and Tpi2 repetitive elements of T. parva Muguga, Tpr1-homologous sequences were detected in two additional species of Theileria. Eight different Tpr1-homol ogous transcripts were present in piroplasm mRNA from a single T. parva Muguga-infected animal, The Tpr1 and Tpr2 amino acid sequences contained six predicted membrane-associated segments, The ratio of synonymous to nonsynonymous substitutions indicates that Tpr1 evolves like protein-encoding DNA, The previously determined nucleotide sequence of the gene encoding the p67 antigen is completely identical in T. parva Muguga, Boleni, and Uganda, including the third base in codons, The data suggest that concerted evolution can lead to the radical divergence of coding sequences and that this can be a mechanism for the generation of novel genes.