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dc.contributor.advisorNagaraja, V
dc.contributor.authorMitra, Anirban
dc.date.accessioned2018-04-11T16:43:19Z
dc.date.accessioned2018-07-30T14:22:15Z
dc.date.available2018-04-11T16:43:19Z
dc.date.available2018-07-30T14:22:15Z
dc.date.issued2018-04-11
dc.date.submitted2013
dc.identifier.urihttp://etd.iisc.ac.in/handle/2005/3382
dc.identifier.abstracthttp://etd.iisc.ac.in/static/etd/abstracts/4248/G25843-Abs.pdfen_US
dc.description.abstractTwo mechanisms, intrinsic and factor-dependent, have evolved for accomplishing the termination of transcription in eubacteria. In this thesis, the first chapter is an introduction to the topic that presents what is known about the mechanisms of termination. The properties of the primary and secondary ‘players’- intrinsic terminators, Rho protein, rho-dependent terminators, RNA polymerse and Nus factors - are presented and the known mechanisms by which termination functions are discussed. In Chapter 2, a detailed analysis of intrinsic terminators – their differential distribution, similarity and divergence - has been penned. The database, compiled using the program GeSTer (Genome Scanner for Terminators), comprises ~2000 sequences and is one of the largest of its kind. Furthermore, analyzing the data from over 700 bacteria reveals how different species have fine-tuned intrinsic terminators to suit their cellular needs. Non-canonical intrinsic terminators emerge to be a significant fraction of the observed structures. The conserved structural features of identified intrinsic terminators are discussed and the relationship between the two modes of termination is assessed. Chapter 3 deals with the importance of transcription termination in regulating horizontally acquired DNA. The results show that genomic islands are scarce in intrinsic terminators and thus constitute most likely sites for Rho-dependent termination. Plausible reasons for why such a scenario has evolved are discussed and a generally applicable model is presented. Chapters 4 and 5 focus on Rho protein from Mycobacterium tuberculosis. In silico identification of M. tuberculosisgenes that rely on MtbRho-dependent termination is followed by experimental validation. The data show that Rho-dependent termination is the predominant mechanism in this species.MtbRho is a majorly expressed protein that governs termination of protein-coding and non-protein coding genes. Further, MtbRho can productively interact with RNA that has considerable secondary structure. Such interactions cause conformational changes in the enzyme. Given that MtbRho has to function with a GC-rich transcriptome, the altered properties could have evolved for optimal function. Taken together, the thesis extends our current understanding of both modes of termination. The importance of non-canonical intrinsic terminators in mycobacteria and other organisms is discussed. The unusual function of Rho and its predominant role in mycobacteria is elucidated. Finally, the inter-relationship between the two modes of termination is also discussed.en_US
dc.language.isoen_USen_US
dc.relation.ispartofseriesG25843en_US
dc.subjectMycobacterium Tuberculosisen_US
dc.subjectMycobacteria - Intrinsic Terminators,en_US
dc.subjectMycobacterium Tuberculosis -Rho-Dependent Termination -en_US
dc.subjectIntrinsic Terminationen_US
dc.subjectMycobacteria - Transcription Terminationen_US
dc.subjectGenetic Transcription - Regulation, Mycobacteriaen_US
dc.subjectRHO Proteins - Mycobacterium Tuberculisisen_US
dc.subjectNon-Canonical Intrinsic Terminatorsen_US
dc.subjectMtbRhoen_US
dc.subjectMycobacterial Genomesen_US
dc.subjectNUS Factors - Intrinsic Terminationen_US
dc.subjectBacterial Transcription Terminationen_US
dc.subjectM. tuberculosis - Rho Factoren_US
dc.subjectMycobacterium tuberculosis - Rho-dependent Terminatorsen_US
dc.subjectMycobacterium - Intrinsic Terminatorsen_US
dc.subject.classificationBacteriologyen_US
dc.titleInsights into Occurrence and Divergence of Intrinsic Terminators and Studies on Rho-Dependent Termination in Mycobacterium Tuberculosisen_US
dc.typeThesisen_US
dc.degree.namePhDen_US
dc.degree.levelDoctoralen_US
dc.degree.disciplineFaculty of Scienceen_US


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