The structure and dynamics of the spliceosome

Elek, Anamaria (2016) The structure and dynamics of the spliceosome. Bachelor's thesis, Faculty of Science > Department of Biology.

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Abstract

Nuclear pre-mRNA splicing is catalysed by the spliceosome, multi-megadalton ribonucleoprotein complex which is assembled in stepwise fashion and activated while bound to its substrate. Defining features of this complex are its size (over 3 MDa), myriad of components (more than 200 proteins and 5 RNAs), and the fact that it is a ribozyme, as well as a metaloenzyme. Evolutionary conserved elements in the secondary structure of RNAs carry out important catalytic functions, such as coordination of catalytic metal ions in the active site, while protein components are found to assist in formation of these secondary structures, as well as in stabilising their interactions. Another important characteristic of the spliceosome is its remarkable plasticity, which is in part due to a large number of intrinsically disordered proteins. This allows for introns from a wide range of vastly different pre-mRNA substrates to be successfully spliced. Splicing must be fast and precise at once, so as to assure that only the correctly spliced and modified RNAs are exported from nucleus to cytoplasm. To achieve this, spliceosome assembly, activation, and catalysis are highly regulated by different posttranslational modifications and through the action of the several enzymes that utilize ATP in order to maintain splicing reaction fidelity. In addition, all of the main reactions in the spliceosome cycle are reversible. Splicing is also, at least to some extent, coordinated with transcription and RNA metabolism which take place in the nucleus. Following the completion of splicing reactions, mature mRNA and intron in the form of lariat sequentially dissociate, as do the components of the spliceosome. These are then recycled in another spliceosome cycle.

Item Type: Thesis (Bachelor's thesis)
Supervisor: Rokov Plavec, Jasmina
Date: 2016
Number of Pages: 43
Subjects: NATURAL SCIENCES > Biology
Divisions: Faculty of Science > Department of Biology
Depositing User: Grozdana Sirotic
Date Deposited: 21 Oct 2016 09:08
Last Modified: 21 Oct 2016 09:08
URI: http://digre.pmf.unizg.hr/id/eprint/5205

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