Uloga transpozona u genomskom doziranju kod vrste Arabidopsis thaliana

undergraduate thesis

• Title (english): Role of transposons in genome dosage response in Arabidopsis thaliana
• Author: Leda Ručević
• Mentor: Ivana Ivančić Baće (mentor)
• Granter: University of Zagreb; Faculty of Science; (Department of Biology); Zagreb
• Defense date and country: 2018, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Biology

Abstract

Nizom istraživanja na Arabidopsis thaliana i drugim biljnim modelnim organizmima utvrđeno je da se s očinske strane triploidna barijera uspostavlja nakupljanjem easiRNA, čija je relativna količina ovisna o genomskoj dozi. U tome važnu ulogu igraju miRNA, to jest specifično miR845a i miR845b, koje su visoko očuvane u većini biljnih porodica, koje stupaju u interakciju s mjestom vezanja početnice LTR retrotranspozona te služe kao okidač za sintezu easiRNA.
Činjenica da prilikom križanja jedinki divljeg tipa i nereduciranih mutanata postoji mala količina vijabilnog sjemena ukazuje na to da postoje prirodne varijacije u količini miR845 u populaciji koje omogućuju da događaji poliploidizacije u prirodi dovedu do specijacije i stvaranja novih biljnih vrsta. Isto tako, činjenica da postotak smanjenja aktivnosti miR845 ne korelira direktno s postotkom vijabilnog sjemena ukazuje na postojanje drugih, još neistraženih puteva uspostavljanja triploidne barijere te da samo djelovanje miR845 nije dovoljno kako bi se uspostavila triploidna barijera.

Abstract (english)

For the longest time, the mechanisms preventing the crossbreeding of certain plant species eluded us. However, a wealth of research conducted in the recent years has shed substantial light on the topic. It has been concluded that the triploid block on the paternal side is established via a kind of counting of chromosomes. An important role in this counting is played by miRNA (specifically miR845a and miR845b in Arabidopsis thaliana), which triggers the dose-dependent acummulation of easiRNA (epigenetically-activated small interfering RNA).
The counting process is conducted in the endosperm of the seed. Owing to the way it is formed, the ratio of maternal to paternal genetic material in the endosperm should be 2:1. If this ratio is disturbed (e.g. an excess of paternal genetic material is detected), the seed aborts.
However, these easiRNA play only a small part in establishing the triploid block. This is demonstrated in part by the small amount of wild type seeds that remain viable despite the triploid block being in place. What’s more, a large part of seeds remain non-viable, even when the activity of miR845 is downregulated. This could in part be due to the role of maternal small RNAs, whose part in establishing the triploid block is still poorly understood.

• Keywords: Arabidopsis thaliana; transpozoni
• Language: croatian
• URN:NBN: urn:nbn:hr:217:774849
• 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: 2018-10-15 12:23:56