CHARACTERIZATION OF THE XRN1 GENE ENCODING A 5'-]3' EXORIBONUCLEASE - SEQUENCE DATA AND ANALYSIS OF DISPARATE PROTEIN AND MESSENGER-RNA LEVELS OF GENE-DISRUPTED YEAST-CELLS
CHARACTERIZATION OF THE XRN1 GENE ENCODING A 5'-]3' EXORIBONUCLEASE - SEQUENCE DATA AND ANALYSIS OF DISPARATE PROTEIN AND MESSENGER-RNA LEVELS OF GENE-DISRUPTED YEAST-CELLS
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DOI：
10.1016/0378-1119(92)90008-d
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发表时间：
1992-10-12
期刊：
影响因子：
3.5
通讯作者：
STEVENS, A
中科院分区：
文献类型：
--
作者：
LARIMER, FW;HSU, CL;STEVENS, A
本实验室克隆的XRN1基因编码160 kda的5‘ -> 3’外核糖核酸酶（XRN1），测序结果表明，该基因与编码DNA链转移酶的基因（DST2或SEP1）以及参与核融合的基因（KEM1）和质粒稳定性的基因（RAR5）相同。为了更好地了解与XRN1缺失相关的各种表型以及与该蛋白相关的酶活性，我们研究了缺乏活性基因（xm1）的酵母细胞的某些特征。细胞更大（平均体积为x 1.5-1.8），倍增时间增加（x 1.9-2.1）。每个细胞的蛋白质合成率是野生型（wt）细胞的80-90%，所得细胞蛋白质水平更高。25S和18S rRNA的合成速率约为wt细胞的45%，细胞水平约为wt细胞的90%。一维PAGE解析的蛋白带水平存在显著差异。对相同蛋白质带的合成速率的观察，以及Northern分析对几种特定mRNA水平的测量，表明mRNA水平存在差异。结果显示，特定短寿命mrna的半衰期延长了两到四倍。在xrn1细胞中发现的蛋白质和RNA种类水平的变化可能是与基因丢失相关的一些表型的原因。
Sequencing of the XRN1 gene of Saccharomyces cerevisiae, cloned in this laboratory as a gene encoding a 160-kDa 5' --> 3' exoribonuclease (XRN1), shows that it is identical to a gene (DST2 or SEP1) encoding a DNA strand transferase and to genes involved in nuclear fusion, KEM1, and plasmid stability, RAR5. To better understand the various phenotypes associated with loss of XRN1 and the enzymatic activities associated with the protein, certain characteristics of our yeast cells lacking an active gene (xm1) have been examined. Cells are larger (average volume is x 1.5-1.8) and have an increased doubling time (x 1.9-2.1). The protein synthesis rate per cell is 80-90% that of wild-type (wt) cells, and the resultant cellular protein levels are higher. The rate of the 25S and 18S rRNA synthesis is approximately 45% that of wt cells and its cellular level is about 90% that of wt cells. Levels of protein bands resolved by one-dimensional PAGE show substantial differences. Synthesis rates observed for the same protein bands, as well as measurements of several specific mRNA levels by Northern analysis, suggest disparities in mRNA levels. Results show two to four times longer half-lives of specific short-lived mRNAs. The variations in levels of protein and RNA species found in the xrn1 cells may be the cause of some of the phenotypes found associated with gene loss.