Abstract
RNase D is a 3'-exoribonuclease whose in vitro specificity has suggested that it is involved in the processing of tRNA precursors. Its in vivo role has remained unclear, however, because mutant cells devoid of the enzyme display no defect in growth or tRNA processing. To learn more about the structure and function of RNase D, we cloned the Escherichia coli rnd gene, which is thought to code for this enzyme. The rnd gene was isolated from a cosmid library based on elevated RNase D activity and was subcloned as a 1.4-kilobase-pair fragment in pUC18. Maxicell analysis of the cloned fragment revealed that a single protein of approximately 40 kilodaltons, which is the size of RNase D, was synthesized. The rnd gene is present as a single copy on the E. coli chromosome and is totally absent in a deletion mutant. Cells that harbored the cloned rnd gene displayed RNase D activity that was elevated as much as 20-fold over that of the wild type. As growth of the culture progressed, however, RNase D specific activity declined dramatically, together with a similar decrease in plasmid copy number. In contrast, no decrease in copy number was observed with an inactive rnd gene. Placement of the rnd gene downstream from the lac promoter led to inducible RNase D overexpression and concomitantly slowed cell growth. These findings support the idea that rnd is the structural gene for RNase D and indicate that elevated RNase D activity is deleterious to E. coli.
Full text
PDF





Images in this article
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Bittner M., Vapnek D. Versatile cloning vectors derived from the runaway-replication plasmid pKN402. Gene. 1981 Dec;15(4):319–329. doi: 10.1016/0378-1119(81)90175-x. [DOI] [PubMed] [Google Scholar]
- Blouin R. T., Zaniewski R., Deutscher M. P. Ribonuclease D is not essential for the normal growth of Escherichia coli or bacteriophage T4 or for the biosynthesis of a T4 suppressor tRNA. J Biol Chem. 1983 Feb 10;258(3):1423–1426. [PubMed] [Google Scholar]
- Casadaban M. J., Chou J., Cohen S. N. In vitro gene fusions that join an enzymatically active beta-galactosidase segment to amino-terminal fragments of exogenous proteins: Escherichia coli plasmid vectors for the detection and cloning of translational initiation signals. J Bacteriol. 1980 Aug;143(2):971–980. doi: 10.1128/jb.143.2.971-980.1980. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Crofton S., Dennis P. P. Cloning and orientation of the gene encoding polynucleotide phosphorylase in Escherichia coli. J Bacteriol. 1983 Apr;154(1):58–64. doi: 10.1128/jb.154.1.58-64.1983. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Cudny H., Deutscher M. P. Apparent involvement of ribonuclease D in the 3' processing of tRNA precursors. Proc Natl Acad Sci U S A. 1980 Feb;77(2):837–841. doi: 10.1073/pnas.77.2.837. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Cudny H., Zaniewski R., Deutscher M. P. Escherichia coli RNase D. Purification and structural characterization of a putative processing nuclease. J Biol Chem. 1981 Jun 10;256(11):5627–5632. [PubMed] [Google Scholar]
- Deutscher M. P. E. coli RNases: making sense of alphabet soup. Cell. 1985 Apr;40(4):731–732. doi: 10.1016/0092-8674(85)90330-7. [DOI] [PubMed] [Google Scholar]
- Donovan W. P., Kushner S. R. Amplification of ribonuclease II (rnb) activity in Escherichia coli K-12. Nucleic Acids Res. 1983 Jan 25;11(2):265–275. doi: 10.1093/nar/11.2.265. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Feinberg A. P., Vogelstein B. A technique for radiolabeling DNA restriction endonuclease fragments to high specific activity. Anal Biochem. 1983 Jul 1;132(1):6–13. doi: 10.1016/0003-2697(83)90418-9. [DOI] [PubMed] [Google Scholar]
- Ghosh R. K., Deutscher M. P. Identification of an Escherichia coli nuclease acting on structurally altered transfer RNA molecules. J Biol Chem. 1978 Feb 25;253(4):997–1000. [PubMed] [Google Scholar]
- Hohn B., Collins J. A small cosmid for efficient cloning of large DNA fragments. Gene. 1980 Nov;11(3-4):291–298. doi: 10.1016/0378-1119(80)90069-4. [DOI] [PubMed] [Google Scholar]
- Larsen J. E., Gerdes K., Light J., Molin S. Low-copy-number plasmid-cloning vectors amplifiable by derepression of an inserted foreign promoter. Gene. 1984 Apr;28(1):45–54. doi: 10.1016/0378-1119(84)90086-6. [DOI] [PubMed] [Google Scholar]
- Nakamura K., Pirtle R. M., Inouye M. Homology of the gene coding for outer membrane lipoprotein within various Gram-negative bacteria. J Bacteriol. 1979 Jan;137(1):595–604. doi: 10.1128/jb.137.1.595-604.1979. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sancar A., Hack A. M., Rupp W. D. Simple method for identification of plasmid-coded proteins. J Bacteriol. 1979 Jan;137(1):692–693. doi: 10.1128/jb.137.1.692-693.1979. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Soberon X., Covarrubias L., Bolivar F. Construction and characterization of new cloning vehicles. IV. Deletion derivatives of pBR322 and pBR325. Gene. 1980 May;9(3-4):287–305. doi: 10.1016/0378-1119(90)90328-o. [DOI] [PubMed] [Google Scholar]
- Southern E. M. Detection of specific sequences among DNA fragments separated by gel electrophoresis. J Mol Biol. 1975 Nov 5;98(3):503–517. doi: 10.1016/s0022-2836(75)80083-0. [DOI] [PubMed] [Google Scholar]
- Yanisch-Perron C., Vieira J., Messing J. Improved M13 phage cloning vectors and host strains: nucleotide sequences of the M13mp18 and pUC19 vectors. Gene. 1985;33(1):103–119. doi: 10.1016/0378-1119(85)90120-9. [DOI] [PubMed] [Google Scholar]
- Zaniewski R., Deutscher M. P. Genetic mapping of mutation in Escherichia coli leading to a temperature-sensitive RNase D. Mol Gen Genet. 1982;185(1):142–147. doi: 10.1007/BF00333804. [DOI] [PubMed] [Google Scholar]
- Zaniewski R., Petkaitis E., Deutscher M. P. A multiple mutant of Escherichia coli lacking the exoribonucleases RNase II, RNase D, and RNase BN. J Biol Chem. 1984 Oct 10;259(19):11651–11653. [PubMed] [Google Scholar]
- Zhu L., Deutscher M. P. tRNA nucleotidyltransferase is not essential for Escherichia coli viability. EMBO J. 1987 Aug;6(8):2473–2477. doi: 10.1002/j.1460-2075.1987.tb02528.x. [DOI] [PMC free article] [PubMed] [Google Scholar]


