Ploidy and Number of Chromosomes in the Alveolate Alga Chromera velia

0498839 - BC 2019 RIV DE eng J - Journal Article
Vazač, J. - Füssy, Zoltán - Hladová, Irena - Killi, Sirisha - Oborník, Miroslav
Ploidy and Number of Chromosomes in the Alveolate Alga Chromera velia.
Protist. Roč. 169, č. 1 (2018), s. 53-63. ISSN 1434-4610. E-ISSN 1618-0941
R&D Projects: GA ČR(CZ) GA16-24027S; GA ČR GA16-10298S
Institutional support: RVO:60077344
Keywords : Life cycles * haploid * tsa-fish * telomere fingerprinting
OECD category: Plant sciences, botany
Impact factor: 3.000, year: 2018

Chromera velia is an alveolate alga which represents the closest known phototrophic relative to apicomplexan parasites. Although the nuclear, mitochondrial, and plastid genomes of this alga have been sequenced, the number of chromosomes and ploidy of C. velia are unknown. We explored ploidy in the vegetative cell, the predominant stage in cultures of Chromera, using the tyramide signal amplification-fluorescence in situ hybridization (TSA-FISH) in isolated nuclei of C. velia. Probes were derived from three single copy genes coding for 4-diphosphocytidyl-2-C-methyl-D-erythritol (CDP-ME) kinase, 2-C-methyl-D-erythritol 2,4-cyclodiphosphate (MEcPP) synthase and Topoisomerase II. Our results indicate that the vegetative cell of C. velia is haploid, as each probe produced a single fluorescent signal, although the possibility of diploidy with somatic pairing of homologous chromosomes cannot be completely excluded. Restriction analysis and hybridization with the telomere probe produced eight bands suggesting the presence of four chromosomes in haploid vegetative cells of C. velia. However, when the chromerid-specific telomere probe (TTTAGGG)(4) was used for TSA-FISH, we consistently obtained a double signal. This may indicate that the four chromosomes are organized in clusters in interphase nuclei of C. velia, which is a chromosome organization similar to that of their apicomplexan relatives. (C) 2017 Elsevier GmbH. All rights reserved.
Permanent Link: http://hdl.handle.net/11104/0291217