Centromeric and non-centromeric satellite DNA organisation differs in holocentric Rhynchospora species

0464891 - BC 2018 RIV DE eng J - Článek v odborném periodiku
Ribeiro, T. - Marques, A. - Novák, Petr - Schubert, V. - Vanzela, A.L.L. - Macas, Jiří - Houben, A. - Pedrosa-Harand, A.
Centromeric and non-centromeric satellite DNA organisation differs in holocentric Rhynchospora species.
Chromosoma. Roč. 126, September 19 (2017), s. 325-335. ISSN 0009-5915. E-ISSN 1432-0886
Grant CEP: GA ČR GBP501/12/G090
Institucionální podpora: RVO:60077344
Klíčová slova: Chromocentre * Cyperaceae * Heterochromatin * Holocentric chromosome
Obor OECD: Genetics and heredity (medical genetics to be 3)
Impakt faktor: 4.021, rok: 2017

Satellite DNA repeats (or satDNA) are fast-evolving sequences usually associated with condensed heterochromatin. To test whether the chromosomal organisation of centromeric and non-centromeric satDNA differs in species with holocentric chromosomes, we identified and characterised the major satDNA families in the holocentric Cyperaceae species Rhynchospora ciliata (2n = 10), R. globosa (2n = 50) and R. tenuis (2n = 2x = 4 and 2n = 4x = 8). While conserved centromeric repeats (present in R. ciliata and R. tenuis) revealed linear signals at both chromatids, non-centromeric, species-specific satDNAs formed distinct clusters along the chromosomes. Colocalisation of both repeat types resulted in a ladder-like hybridisation pattern at mitotic chromosomes. In interphase, the centromeric satDNA was dispersed while non-centromeric satDNA clustered and partly colocalised to chromocentres. Despite the banding-like hybridisation patterns of the clustered satDNA, the identification of chromosome pairs was impaired due to the irregular hybridisation patterns of the homologues in R. tenuis and R. ciliata. These differences are probably caused by restricted or impaired meiotic recombination as reported for R. tenuis, or alternatively by complex chromosome rearrangements or unequal condensation of homologous metaphase chromosomes. Thus, holocentricity influences the chromosomal organisation leading to differences in the distribution patterns and condensation dynamics of centromeric and non-centromeric satDNA.
Trvalý link: http://hdl.handle.net/11104/0275267