Regulacija metilacije DNA biljaka malim molekulama RNA

undergraduate thesis

• Title (english): Regulation of plants' DNA methylation by small RNA molecules
• Author: Josip Šafran
• Mentor: Dunja Leljak-Levanić (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

Male RNA molekule imaju bitnu ulogu u eukariotskim stanicama. Zbog svoje karakteristične funkcije i dužine podijeljene su u nekoliko razreda. Najbrojnije su miRNA, piRNA i siRNA. Modelni organizam za proučavanje biosinteze i funkcije ovih molekula je biljka A.thaliana. Heterokromatin interferirajuća siRNA regulira transkripcijsko utišavanje gena izazivanjem DNA metilacije i dimetilacije H3K9. RNA posredovana DNA metilacija (RdDM) je glavni epigenetski put posredovan malim molekulama RNA kod biljaka. RdDM zahtijeva specifičnu transkripcijsku mašineriju koja se sastoji od dvije polimeraze, Pol IV i Pol V, specifične za biljke, i velikog broja pratećih proteina čija se uloga kod RdDM samo djelomično razumije. Najbitniji od njih su DCL3, RDR2 i AGO4. Dva su moguća puta utišavanja RNA molekulama. Kod prvoga male RNA uzrokuju transkripcijsko utišavanje gena formiranjem heterokromatina, a kod drugog dolazi do postranskripcijskog utišavanja degradacijom mRNA ili inhibicijom translacije. Male RNA molekule mogu nastati transkripcijom od endogenih lokusa ali i sa virusnih i transgenih nukleinskih kiselina. MiRNA i siRNA djeluju u somatskim i generativnim stanicama kod širokog spektra eukariotskih organizama u kojima sudjeluju u raznim funkcijama, od regulacije transpozona, biosinteze biljnih hormona do razvoja cvijeta i listova.

Abstract (english)

Small RNA molecules have an important function in eukaryotic cells. Having a rather characteristic function and length, they are divided into several classes. The most abundant ones are miRNA, piRNA and siRNA. The model organism used for the study of biosynthesis and functions of these molecules is a plant A.thaliana. Heterochromatin interfering siRNA regulates transcriptional silencing of genes by inducing DNA methylation and dimethylation of H3K9. RNA directed DNA methylation (RdDM) is the main epigenetic pathway which is in plants directed by small RNA molecules. RdDM requires a specific transcription machinery which consists of two polymerases that are rather specific for plants - Pol IV and Pol V – and a large number of accompanying proteins whose function in RdDM is not entirely clear. The most important of these proteins are DCL3, RDR2 and AGO4. There are two possible ways of RNA silencing by using molecules. In the first instance, small RNA molecules cause transcriptional silencing of genes by forming heterochromatin and in the second, post-transcriptional silencing occurs because of mRNA degradation or inhibition of translation. Small RNA molecules are created by transcription from endogenous locus, as well as viral and transgenic nucleic acids. MiRNA and siRNA operate in somatic and generative cells in a broad spectrum of eukaryotic organisms where they participate in various functions - from regulation of transposons and biosynthesis of plant hormones to the development of the flower and leaves.

• Keywords: male RNA molekule
• Keywords (english): small RNA molecules
• Language: croatian
• URN:NBN: urn:nbn:hr:217:663131
• Study programme: Title: Ecology; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) biologije (sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) biologije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2017-12-18 12:54:44