Zaštitna uloga proteina iz tardigrada protiv oštećenja DNA

undergraduate thesis

• Title (english): Protective role of tardigrade proteins against DNA damage
• Author: Karlo Miškec
• Mentor: Ivana Ivančić Baće (mentor)
• Granter: University of Zagreb; Faculty of Science; (Department of Biology); Zagreb
• Defense date and country: 2017, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Biology

Abstract

Tardigrade ili vodeni medvjedići su beskralježnjaci koji pripadaju koljenu Tardigrada. Većina tardigrada je barem djelomično tolerantna na stresne uvjete kao što su suša, promjene saliniteta, visoki pritisak i radioaktivna zračenja. Smatra se da njihova tolerancija dolazi zbog intenzivnog horizontalnog prijenosa gena pri čemu se većinom prenose geni za stres otporne proteine ili proteine koji neutraliziraju oksidativni stres poput katalaza. Sekvenciranjem genoma ekstremotolerantne vrste R. varieornatus dokazano je da HGT ipak nije nužno glavni razlog tolerancije pošto ova vrsta ima nižu stopu HGT-a (1.2%) od vrste H. dujardini (17.5%) koja ima manju toleranciju. R. varieornatus vjerojatno ima ekstremnu toleranciju zbog gubitka određenih metaboličkih puteva kao što je peroksisomalna ß-oksidacija zbog čega se smanjuje udio H2O2 u stanici i supresije autofagije kojom se sprečava uništavanje komponenta stanice. Što se tiče intenzivne radiotolerancije, protein Dsup je najvjerojatniji razlog ovog fenomena. On se veže svojim C-terminalnim krajem te smanjuje oštećenje DNA i povećava vijabilnost. Transfekcijom stanica HEK293 dokazano je da protein Dsup može povećati radiotoleranciju ljudskih stanica u kulturi te smanjiti oštećenja DNA koja su nastala zračenjem za 40%.

Abstract (english)

Tardigrades or water bears are invertebrates from phylum Tardigrada. Most tardigrades are at least partially tolerant to stress conditions like drought, changes in salinity, high pressure and radiation. It is thought that their tolerance comes from intense horizontal gene transfer most of which are genes for stress tolerant proteins or proteins that neutralise oxidative stress like catalases. After sequencing the genome of extremotolerant species R. varieornatus, it was proven that HGT is not the main reason of tolerance since this species has lower HGT (1.2%) than species H. dujardini (17.5%) which has lower tolerance. R. varieornatus probably has extreme tolerance due to losing specific metabolic pathways like peroxisosmal ß-oxidation which lowers the amount of H2O2 in the cell and autophagy supression which prevents the destruction of cellular components. As for intense radiotolerance, Dsup protein is the most probable cause of this phenomenon. This protein binds DNA with its C-terminal end, reduces DNA damage and increases viability. Dsup protein increases radiotolerance in transfected HEK293 human cell culture and reduces DNA damage caused by radiation by 40%.

• Keywords: tardigrade; oštećenja DNA
• Keywords (english): tardigrades; DNA damage
• Language: croatian
• URN:NBN: urn:nbn:hr:217:268491
• 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: 2017-09-18 12:39:20