Struktura telomere i uloga telomernih proteina

undergraduate thesis

• Title (english): Structure of telomere and role of telomeric proteins
• Author: Dora Markulin
• Mentor: Maja Matulić (mentor)
• Granter: University of Zagreb; Faculty of Science; (Department of Biology); Zagreb
• Defense date and country: 2009, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Biology

Abstract

Telomere su zaštitne strukture na krajevima linearnih kromosoma koje su nužne na staničnoj razini za stabilnost genoma, dok na razini organizma sudjeluju u procesu starenja koji ima funkciju tumorske supresije. Telomere mogu regulirati duljinu životnog vijeka stanica i štite prirodne krajeve kromosoma od neželjenih aktivnosti popravka DNA kao što su nehomologno spajanje krajeva DNA i homologna rekombinacija. Kromosomi imaju na svojim krajevima telomernu DNA s uzastopnim ponavljanjem heksanukleotidne sekvence koja oblikuje omčastu strukturu uz pomoć specifičnih proteina, tzv. T petlju. Šelterin, zaštitni proteinski kompleks, sastoji se od šest proteina: TRF1, TRF2, TIN2, Rap1, TPP1 i POT1 koji su međusobno povezani i vežu telomernu sekvencu. Inhibicija TRF2 rezultira poremećajem telomernih struktura, aktivacijom p53 i procesima apoptoze ili starenja, odnosno fuzijom krajeva kromosoma, ovisno o tipu stanica. Najnovijim je istraživanjima dokazano da se na telomerama nalazi i velika nekodirajuća RNA koja stvara cjelovitu komponentu telomernog heterokromatina, TERRA. Na temelju njene funkcije, zaključeno je da je takva RNA uključena u regulaciju enzima telomeraze i remodeliranje kromatina tijekom razvoja i diferencijacije stanice.

Abstract (english)

Telomeres are protective structures at the ends of linear chromosomes. They are critical at the cellular level for maintenance of the genome stability. At the organismal level they may contribute to ageing, which is considered to be tumor supressing mechanism. They can regulate the lifespan of cells and protect natural chromosome ends from unwanted DNA repair activities, such as non-homologous end joining and homologous recombination. The chromosomes end in telomeric DNA containing tandem hexanucleotid repeats in specific loop structure. The complex of specific proteins, named Shelterin, takes part in the maintenance of the T loop and telomere function. Shelterin consists of six proteins: TRF1, TRF2, TIN2, Rap1, TPP1 and POT1. The complex has a high affinity toward telomeric sequence. TRF2 inhibition compromises the structure of the telomeres and can cause p53 activation, apoptosis or cell senescence as well as chromosome end fusion, depending on the cell type. The recent investigations had identified telomeric repeat containing RNA, TERRA, a large noncoding RNA forming an integral component of telomeric heterochromatin. TERRA functions suggest important roles in the regulation of telomerase and in orchestrating chromatin remodelling throughout development and cellular differentiation.

• Keywords: telomere; telomerni proteini
• Keywords (english): telomeres; telomeric proteins
• Language: croatian
• URN:NBN: urn:nbn:hr:217:645998
• 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: 2018-03-13 11:50:18