RNase HI Is Essential for Survival of Mycobacterium smegmatis |
| |
| Authors: | Alina E Minias Anna M Brzostek Malgorzata Korycka- Machala Bozena Dziadek Piotr Minias Malini Rajagopalan Murty Madiraju Jaroslaw Dziadek |
| |
| Institution: | 1Institute of Medical Biology, Polish Academy of Sciences, Lodz, Poland;2Department of Immunoparasitology, University of Lodz, Lodz, Poland;3Department of Teacher Training and Biodiversity Studies, University of Lodz, Lodz, Poland;4Department of Microbiology, University of Texas Health Center at Tyler, Tyler, Texas, United States of America;University of Delhi, INDIA |
| |
| Abstract: | RNases H are involved in the removal of RNA from RNA/DNA hybrids. Type I RNases H are thought to recognize and cleave the RNA/DNA duplex when at least four ribonucleotides are present. Here we investigated the importance of RNase H type I encoding genes for model organism Mycobacterium smegmatis. By performing gene replacement through homologous recombination, we demonstrate that each of the two presumable RNase H type I encoding genes, rnhA and MSMEG4305, can be removed from M. smegmatis genome without affecting the growth rate of the mutant. Further, we demonstrate that deletion of both RNases H type I encoding genes in M. smegmatis leads to synthetic lethality. Finally, we question the possibility of existence of RNase HI related alternative mode of initiation of DNA replication in M. smegmatis, the process initially discovered in Escherichia coli. We suspect that synthetic lethality of double mutant lacking RNases H type I is caused by formation of R-loops leading to collapse of replication forks. We report Mycobacterium smegmatis as the first bacterial species, where function of RNase H type I has been found essential. |
| |
| Keywords: | |
|
|
