Genomski rearanžmani u bakteriji Deinococcus radiodurans: Uloga proteina RecG

master's thesis

• Title (english): Genomic reagents in Deinococcus radiodurans: the role of Protein RecG
• Author: Ana Hleb
• Mentor: Nataša Hulak (mentor)
• Committee member: Nataša Hulak (predsjednik povjerenstva)
• Committee member: Ksenija Zahradka (član povjerenstva)
• Committee member: Luna Maslov Bandić (član povjerenstva)
• Committee member: Dušica Vujaklija (član povjerenstva)
• Granter: University of Zagreb; Faculty of Agriculture; (Microbiology); Zagreb
• Defense date and country: 2018-12-18, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Agronomy

Abstract

Bakterija Deinococcus radiodurans spada u skupinu organizama koji su se prilagodili životu u ekstremnim uvjetima. Izuzetno je otporna na razne faktore koji uzrokuju oštećenja molekule DNA poput UV zračenja, ionizacijskog zračenja, isušivanja te izlaganja kemijskim mutagenim spojevima. Ono što najviše plijeni pažnju kod bakterije D. radiodurans je njena otpornost na visoke doze ionizacijskog zračenja, točnije x-zraka i gama zraka; može preživjeti dozu zračenja od 20000 Gy, što je 3000 puta veća doza od one koja se smatra letalnom za čovjeka. Najteži tip oštećenja genoma nakon zračenja predstavljaju dvolančani lomovi DNA. Oni se u bakteriji D. radiodurans popravljaju posebnim mehanizmom koji se bazira na homolognoj rekombinaciji te uključuje opsežnu sintezu DNA. Ključnu ulogu u ovom popravku ima protein RecA. U bakterijama mutiranima u genu recA odvija se RecA-neovisni popravak koji je, međutim, slabo učinkovit, neprecizan i dovodi do velikih genomskih rearanžmana. Cilj ovog rada bio je istražiti učinak mutacije recG na popravak DNA i genomsku nestabilnost recA mutanata bakterije D. radiodurans. Ispitali smo preživljenje mutanata recA i recA recG nakon UV i gama zračenja, a metodom elektroforeze u promjenjivom električnom polju analizirali smo DNA stanica koje su preživjele 2 kGy gama zračenja. Dobiveni rezultati pokazuju da su mutanti recA recG podjednako osjetljivi na zračenje kao i mutanti recA, no za razliku od njih, ne stvaraju velike genomske rearanžmane.

Abstract (english)

Bacterium Deinococcus radiodurans belongs to the group of organisms adapted to the life in extreme conditions. It is extremely resistant to various agents that cause damage to DNA molecules such as UV radiation, ionizing radiation, desiccation and exposure to various mutagenic compounds. The most interesting feature of D. radiodurans is its resistance to high doses of ionizing radiation, namely x-rays and gamma rays; it can survive the dose of 20,000 Gy, which is 3,000 fold higher than the dose that is lethal for a human. The most severe form of genomic damage after radiation is double-strand DNA breaks. In D. radiodurans double-strand DNA breaks are repaired by a special mechanism that is based on homologous recombination, and which involves extensive DNA synthesis. The key role in this mechanism is played by the RecA protein. In D. radiodurans cells mutated in the recA gene, a RecA-independent repair takes place, which is, however, less efficient, inaccurate and leads to gross genome rearrangements. The aim of this work was to investigate the effect of a recG mutation on DNA repair and genomic instability of D. radiodurans recA mutants. We examined survival after UV and gamma radiation in recA and recA recG mutants and analyzed their DNA by pulsed-field gel electrophoresis. Our results showed that the recA recG mutants are as sensitive to radiation as the recA mutants, but do not produce gross genome rearrangements.

• Keywords: Deinococcus radiodurans; gama zračenje; homologna rekombinacija; protein RecA; protein RecG
• Keywords (english): Deinococcus radiodurans; gamma radiation; homologous recombination; RecA protein; RecG protein
• Language: croatian
• URN:NBN: urn:nbn:hr:204:153360
• Study programme: Title: Agroecology; Study programme type: university; Study level: graduate; Academic / professional title: magistar/ magistra inženjer/inženjerka agroekologija (magistar/ magistra inženjer/inženjerka agroekologija)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2019-01-10 07:49:32