Structure, expression, and phylogenetic relationships of a family of ypt genes encoding small G-proteins in the green alga Volvox carteri
Structure, expression, and phylogenetic relationships of a family of ypt genes encoding small G-proteins in the green alga Volvox carteri
复制标题
绿藻Volvox carteri中编码小G蛋白的ypt基因家族的结构、表达和系统发育关系
作者：
S. Fabry;Anja Jacobsen;H. Huber;K. Palme;R. Schmitt
除了先前描述的编码小G蛋白的基因yptV 1，我们现在已经从绿色团藻中鉴定并测序了另外四个ras相关的ypt基因（yptV 2-yptV 5）。这四个新基因编码由203至217个氨基酸残基组成的多肽，这些氨基酸残基含有Ras超家族ypt/rab亚组的典型序列元件（GTP结合结构域、效应结构域）。从V. carteriypt基因产物衍生的氨基酸序列与其他物种的Ypt同源物的比较显示，相似性值范围从60%到85%，而种内相似性被发现只有55%。编码序列被占据基因中不同位置的可变大小（70-1000个核苷酸）的5-7个内含子中断。用yptV 1、yptV 3、yptV 4和yptV 5特异性引物对阶段特异性RNA的逆转录样品进行PCR扩增，以确定yptV转录是否可能限于细胞类型或生命周期的特定阶段。这些实验表明，这些基因中的每一个都在团藻的整个生命周期中表达，并且在团藻的体细胞和生殖细胞中表达。通过引物延伸定位yptV 1和yptV 5的转录起始位点。重组yptV cDNA在E.大肠杆菌产生的重组蛋白结合GTP特异性，表现出的属性是典型的小G蛋白。衍生的YptV多肽序列用于将它们分成四种不同类别的Ras样蛋白。这些是Ras超家族的第一个在绿色染色体中被鉴定的蛋白质。我们讨论的YptV蛋白在团藻细胞内囊泡运输的可能作用。
In addition to the previously described gene yptV1 encoding a small G-protein we have now identified and sequenced four more ras-related ypt genes (yptV2-yptV5) from the green alga Volvox carteri. The four new genes encode polypeptides consisting of 203 to 217 amino-acid residues that contain the typical sequence elements (GTP-binding domains, effector domain) of the ypt/rab subgroup of the Ras superfamily. Comparison of the derived amino-acid sequences from the V. carteri ypt gene products and their Ypt homologs from other species revealed similarity values ranging from 60% to 85%, whereas intraspecies similarities were found to approach only 55%. The coding sequences are interrupted by 5–7 introns of variable size (70–1000 nucleotides) occupying different positions in the genes. Reverse-transcribed samples of stage-specific RNAs were PCR-amplified with primers specific to yptV1, yptV3, yptV4, and yptV5 to determine if yptV transcription might be restricted to either cell type or to a specific stage of the life cycle. These experiments demonstrated that each of these genes is expressed throughout the entire Volvox life cycle and in both the somatic and the reproductive cells of the alga. The transcription start sites of yptV1 and yptV5 were mapped by primer extension. Expression of recombinant yptV cDNA in E. coli yielded recombinant proteins that bound GTP specifically, demonstrating a property which is typical for small G-proteins. The derived YptV polypeptide sequences were used to group them into four distinct classes of Ras-like proteins. These are the first proteins of the Ras superfamily to be identified in a green alga. We discuss the possible role of the YptV-proteins in the intracellular vesicle transport of Volvox.
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影响因子：
10.7
作者：
A. Larson;M. Kirk;D. Kirk
通讯作者：
A. Larson;M. Kirk;D. Kirk
寻找团藻及其亲属细胞分化的分子起源。
DOI：
10.1016/s0074-7696(08)61413-8
发表时间：
1992
期刊：
International review of cytology
影响因子：
--
作者：
Schmitt,R;Fabry,S;Kirk,DL
通讯作者：
Kirk,DL
影响因子：
2.7
作者：
L. Tam;D. Kirk
通讯作者：
L. Tam;D. Kirk
团藻发育和进化的遗传、生化和分子方法。
DOI：
10.1016/s0074-7696(08)61428-x
发表时间：
1986
期刊：
International review of cytology
影响因子：
--
作者：
Kirk,DL;Harper,JF
通讯作者：
Harper,JF
酵母 RAS 基因。
DOI：
10.1016/0304-419x(88)90002-9
发表时间：
1988
期刊：
Biochimica et biophysica acta
影响因子：
--
作者：
Tamanoi,F
通讯作者：
Tamanoi,F