Revisiting intrinsic transcription termination in mycobacteria: U-tract downstream of secondary structure is dispensable for termination

Ahmad, E and Hegde, SR and Nagaraja, V (2020) Revisiting intrinsic transcription termination in mycobacteria: U-tract downstream of secondary structure is dispensable for termination. In: Biochemical and Biophysical Research Communications, 522 (1). pp. 226-232.

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Abstract

In Escherichia coli, G/C-rich hairpin structure followed by a U-tract in the 3′ region of the nascent RNA are crucial determinants for intrinsic or factor independent transcription termination. In mycobacteria, there is a scarcity of such intrinsic terminators. However, secondary structures having G/C-rich stem devoid of any U's or with suboptimal U-tracts were identified earlier as terminators and found to be functional both in vitro and in vivo. Two different observations - that a mycobacterial RNA polymerase (RNAP) does not function at intrinsic terminators devoid of U-tracts and the identification of an altogether new motif for termination in mycobacteria necessitated re-examining a number of putative terminators for their function as terminators. When these in silico identified non-canonical terminators were subjected to experimental validation, they were found to dissociate RNA from the elongating RNAP. Termination is observed when the U-tracts were reduced, or totally absent both in vitro and in vivo. Our results, thus indicate that the presence of U-tract following the G/C-rich stem in an intrinsic terminator may not be an essential determinant for transcription termination in mycobacteria

Item Type:	Journal Article
Publication:	Biochemical and Biophysical Research Communications
Publisher:	Elsevier B.V.
Additional Information:	The copyright for this article belongs to the Elsevier B.V.
Keywords:	RNA polymerase; short hairpin RNA; bacterial RNA, 3' untranslated region; Article; bacterial strain; computer model; controlled study; Escherichia coli; gene expression; gene structure; in vitro study; in vivo study; Mycobacterium; nonhuman; plasmid; priority journal; RNA structure; transcription elongation; transcription termination; tuberculosis; validation study; chemistry; conformation; gene expression regulation; genetic transcription; genetics; human; microbiology; mycobacteriosis; Mycobacterium; nucleotide sequence; regulator gene, Base Sequence; Gene Expression Regulation, Bacterial; Humans; Mycobacterium; Mycobacterium Infections; Nucleic Acid Conformation; RNA, Bacterial; Terminator Regions, Genetic; Transcription, Genetic
Department/Centre:	Division of Biological Sciences > Microbiology & Cell Biology
Date Deposited:	02 Feb 2023 09:44
Last Modified:	02 Feb 2023 09:44
URI:	https://eprints.iisc.ac.in/id/eprint/79761

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