Introni grupe I u bakterijama

undergraduate thesis

• Title (english): Bacterial group I introns
• Author: Adriana Vučetić
• Mentor: Ivana Ivančić Baće (mentor)
• Granter: University of Zagreb; Faculty of Science; (Department of Biology); Zagreb
• Defense date and country: 2015, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Biology

Abstract

Introni grupe I su intervencijski sljedovi koji se nalaze unutar tRNA, rRNA i protein kodirajućih gena u bakterijama i bakteriofagima, te su također pronađeni u genima jezgre, kloroplasta i mitohondrija eukariota. Ovi introni se nalaze unutar RNA gena i njihovo prekrajanje iz prekursorske RNA je katalizirano vlastitom ribozimskom aktivnošću, kao posljedica dobro definirane tercijarne strukture. Efikasno prekrajanje introna grupe I in vivo najčešće zahtijeva interakcije sam staničnim RNA - vezujućim proteinima ili faktorima kodiranim od samih introna koji omogućuju stvaranje strukture kompetentne za prekrajanje. Neki samoizrezujući introni kodiraju ciljajuće endonukleaze (HEaze) koje imaju sposobnost širenja introna u alele bez introna, stoga su neki introni pokretni genetički elementi. Introni grupe I imaju ograničenu rasprostranjenost među bakterijama i smatra se da nemaju utjecaj na fenotip. Međutim neki introni imaju prilagođene funkcije tako da djeluju kao riboprekidači ili je došlo do udomaćivanja gena za HEaze što upućuje da mogu biti izvor novih genetičkih elemenata. Jedno od najzanimljivijih pitanja je evolucijsko porijeklo pokretnih introna grupe I. Trenutačno se smatra da HEaze i pokretni introni grupe I imaju različito porijeklo.

Abstract (english)

Group I introns are intervening sequences that have invaded tRNA, rRNA and protein coding genes in bacteria and their phages, and are also found in the nuclear, chloroplast and mitochondrial genomes of eukaryotes. These introns interrupt RNA genes, and their splicing from precursor RNAs is catalyzed by acting as ribozymes, by folding to a well-defined three-dimensional structure. Efficient in vivo splicing of group I introns often requires interaction with cellular RNA-binding proteins or with intron-encoded factors that promote the formation of splicing-competent RNA structures. Some group I introns are mobile genetic elements due to encoded homing endonuclease (HEases) genes that promote their spread to intronless alleles. Group I introns have a limited distribution among bacteria and the current assumption is that they are phenotypically neutral, yet the co-opting of intron functions by a riboswitch or the domestication of intron-encoded homing endonuclease as a regulatory protein indicates that introns can be a source of genetic novelty. One of the most intriguing questions about mobile group I introns concerns their evolutionary origin. The current consensus is that HEases and group I introns had distinct evolutionary origins.

• Keywords: Introni grupe I; bakterije
• Keywords (english): group I introns; bacteria
• Language: croatian
• URN:NBN: urn:nbn:hr:217:647062
• Study programme: Title: Molecular Biology; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) molekularne biologije (sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) molekularne biologije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2017-12-19 09:18:35