Inicijacija replikacije bez ishodišta replikacije

undergraduate thesis

• Title (english): The initiation of replication without the origin of replication
• Author: Monika Vranić
• Mentor: Ivana Ivančić Baće (mentor)
• Granter: University of Zagreb; Faculty of Science; (Department of Biology); Zagreb
• Defense date and country: 2014, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Biology

Abstract

Inicijacija replikacije DNA započinje s definiranih ishodišta replikacije, što je zajedničko trima domenama života – prokariotima, eukariotima i arhejama. Ishodišta se među domenama razlikuju po broju i strukturi, kao i po mašineriji koja upravlja njome. Virusi, također, iniciraju replikaciju vlastitog genoma s definiranih ishodišta, iako su vrlo zastupljeni alternativni mehanizmi inicijacije – homolognom rekombinacijom ili transkripcijom. Cilj je ovog seminara bio upoznati se s eksperimentalnim pristupom proučavanja dinamike replikacije i karakterizacije ishodišta replikacije, a ponajviše upoznati se s alternativnim načinom inicijacije replikacije u kompleksnijem organizmu od virusa. To su arheje – organizmi strukturno sličniji prokariotima, a po molekularnoj mašineriji sličniji eukariotima. Pokazalo se da inicijacija replikacije u mutantima ΔoriC arheje Haloferax volcanii kao i vijabilnost stanice ovisi o proteinu RadA, koji je uključen u popravak oštećenja DNA homolognom rekombinacijom te u inicijaciju replikacije čitavog genoma stanice. Stoga, potrebna su dodatna istraživanja replikacijske mašinerije uključene u ovakav mehanizam replikacije. Također, nužno je proučiti strukturu regija DNA na kojima je moguće stvaranje D-omče ili R-omče koje su zamjena izvorištima replikacije. Nadalje, upitna je svrha postojanja ishodišta replikacije, budući da stanice Haloferax volcanii pokazuju bolji rast kada ne sadrže ishodišta u genomu. Velika je vjerojatnost da su ishodišta sebični genetski elementi koji su kroz evoluciju preuzeli kontrolu nad prethodno poliploidnim organizmima.

Abstract (english)

The initiation of DNA replication begins at defined origins of replication, which is common across the three domains of life - prokaryotes, eukaryotes and archaea. Origins differ across the domains in number and structure, as well as in the machinery that controls it. Viruses also initiate replication of the genome using its own defined origins, although alternative mechanisms of initiation are highly represented - homologous recombination or transcription. The aim of this seminar was to become acquainted with the experimental approach of studying the dynamics of replication and characterization of the origin of replication, and mostly to become familiar with alternative ways of initiation of replication in more complex organism than viruses. These are archaea – organisms which are structurally similar to prokaryotes, and which are, by the molecular machinery, similar to eukaryotes. It has been shown that the initiation of replication in ΔoriC mutant of Haloferax volcanii, as well as the viability, depended on the RadA protein which is involved in DNA damage repair by homologous recombination. This suggested that the initiation of replication was stimulated by recombination. Additional research of the DNA replication machinery involved in this mechanism of replication is required. Also, it will be necessary to analyze the DNA regions where D-loop or R-loop could be created. Furthermore, the purpose of existence of the origin of replication is questionable, since Haloferax volcanii cells showed better growth without origins of replication. It is very likely that the origins of replication are selfish genetic elements that took control of previously polyploid organisms throughout the evolution.

• Keywords: inicijacija replikacije DNA
• Keywords (english): initiation of DNA replication
• Language: croatian
• URN:NBN: urn:nbn:hr:217:954976
• 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: 2017-12-11 13:44:54