Universität zu Köln

Salinas Gamboa, Rigel ORCID: 0000-0001-6912-6013 (2025). Mechanisms for prevention of recombination at centromeric regions in Arabidopsis thaliana. PhD thesis, Universität zu Köln.

PDF (This document contains the final version with the Publication Format) ThesisRSG_Mechanisms for prevention of recombination at centromeric regions in Arabidopsis thaliana_24_09-Publication.pdf - Published Version Download (3MB)

Abstract

Most organisms show typically 1 to 3 crossovers (COs) along the chromosome per meiosis; however, in the centromere and pericentromere region COs are strongly repressed by a largely unknown mechanism. Several pathways were shown to negatively regulate CO formation; while the corresponding mutants have a massive CO increase along the chromosome (up to >6 fold), COs are not increased in the peri-centromeric regions. Suggesting the presence of another pathway that specifically restrain CO formation in the centromere region, possibly in a redundant manner with the known anti-CO mechanisms and DNA methylation. This project aims to understand mechanisms that settle the patterns of distribution of COs along the chromosomes by identifying anti-CO factors acting in pericentromeric regions, through a genetic screen. We tested candidate mutants, notably some with modified behaviour of centromere and kinetochore and analysed their recombination frequency through Fluorescent Transgenic Lines (FTLs) expressed in seeds, and genetic markers both flaking centromeric regions. We found 1 to 1,5-fold increase recombination in three mutants: ARABIDOPSIS SUMO PROTEASE (asp2), CHROMOSOME TRANSMISSION FIDELITY (ctf18) and SHUGOSHIN 2 (sgo2), in comparison to wild type. Double mutants of these genes and with CHROMOMETHYLASE 3 (cmt3) were also analysed, finding notable cumulative effects in most of them, except for the asp2 sgo2 combination, suggesting there are at least three different pathways regulating CO formation in centromeric regions Asp2/Sgo2, Ctf18 and Cmt3.

Item Type:	Thesis (PhD thesis)
Creators:	Creators Email ORCID ORCID Put Code Salinas Gamboa, Rigel rigelsalinasgamboa@gmail.com https://orcid.org/0000-0001-6912-6013 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-792641
Date:	2025
Place of Publication:	Köln
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Außeruniversitäre Forschungseinrichtungen > MPI for Plant Breeding Research
Subjects:	Life sciences Technology (Applied sciences) Agriculture
Uncontrolled Keywords:	Keywords Language Meiosis English Recombination English Centromeres and pericentromeres English Centromeric cohesion English Traffic lines English Crossovers (COs) English deSUMOylase English CTF18 English SGO2 English ASP2 (SPF2) English
Date of oral exam:	4 December 2023
Referee:	Name Academic Title Mercier, Raphael Prof. Dr. Tomma, Bart Prof. Dr. Kopriva, Stanislav Prof. Dr.
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/79264