THE MYXOCOCCUS-XANTHUS DSG GENE-PRODUCT PERFORMS FUNCTIONS OF TRANSLATION INITIATION-FACTOR IF3 IN-VIVO
THE MYXOCOCCUS-XANTHUS DSG GENE-PRODUCT PERFORMS FUNCTIONS OF TRANSLATION INITIATION-FACTOR IF3 IN-VIVO
复制标题
DOI：
10.1128/jb.176.5.1434-1442.1994
复制
发表时间：
1994-03-01
影响因子：
3.2
通讯作者：
KAISER, D
中科院分区：
文献类型：
--
作者：
KALMAN, LV;CHENG, YL;KAISER, D
Dsg蛋白的氨基酸序列与大肠杆菌的翻译起始因子IF 3（其infC基因的产物）的氨基酸序列有50%相同。抗大肠coli IF 3抗体与Dsg蛋白交叉反应。dsg中的tn 5插入突变是致命的。然而，当有充足的营养时，某些dsg点突变株的生长速度与野生型细胞相同。在诱导子实体发育的饥饿条件下，这些dsg突变体开始聚集但不能进一步发育。作为总细胞蛋白的一部分，Dsg抗原的水平在生长和发育期间没有可检测的变化，正如蛋白质合成所必需的因子所预期的那样。在E.已知大肠杆菌在翻译水平上是自动调节的。这种自动调节在E. coliinfC 362错义突变体。来自黄色粘球菌的dsg（+）基因恢复infC 362突变株的正常自动调节。Dsg与E.大肠杆菌、其它肠道细菌和嗜热脂肪芽孢杆菌，具有66个氨基酸的C-末端尾。这条尾巴的部分和完全缺失表明，它是需要某些营养和发育功能，但不是生活力。
The amino acid sequence of the Dsg protein is 50% identical to that of translation initiation factor IF3 of Escherichia coli, the product of its infC gene. Anti-E. coli IF3 antibodies cross-react with the Dsg protein. Tn5 insertion mutations in dsg are lethal. When ample nutrients are available, however, certain dsg point mutant strains grow at the same rate as wild-type cells. Under the starvation conditions that induce fruiting body development, these dsg mutants begin to aggregate but fail to develop further. The level of Dsg antigen, as a fraction of total cell protein, does not change detectably during growth and development, as expected for a factor essential for protein synthesis. The amount of IF3 protein in E. coli is known to be autoregulated at the translational level. This autoregulation is lost in an E. coli infC362 missense mutant. The dsg(+) gene from Myxococcus xanthus restores normal autoregulation to the infC362 mutant strain. Dsg is distinguished from IF3 of E. coli, other enteric bacteria, and Bacillus stearothermophilus by having a C-terminal tail of 66 amino acids. Partial and complete deletion of this tail showed that it is needed for certain vegetative and developmental functions but not for viability.