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- Title
Sister Chromatids Are Often Incompletely Aligned in Meristematic and Endopolyploid Interphase Nuclei of Arabidopsis thaliana.
- Authors
Schubert, Veit; Klatte, Marco; Pecinka, Ales; Meister, Armin; Jasencakova, Zuzana; Schubert, Ingo
- Abstract
We analyzed whether sister chromatids are continuously aligned in meristematic and endopolyploid Arabidopsis interphase nuclei by studying sister-chromatid alignment at various chromosomal positions. FISH with individual BACs to flow-sorted 4C root and leaf nuclei frequently yielded more than two hybridization signals, indicating incomplete or absent sister-chromatid alignment. Up to 100% of 8C, 16C, and 32C nuclei showed no sister-chromatid alignment at defined positions. Simultaneous FISH with BACs from different chromosomal positions revealed more frequent sister-chromatid alignment in terminal than in midarm positions. Centromeric positions were mainly aligned up to a ploidy level of 16C but became separated or dispersed in 32C nuclei. DNA hypomethylation (of the whole genome) and transcriptional activity (at FWA gene position) did not impair sister-chromatid alignment. Only 6.1% of 4C leaf nuclei showed sister-chromatid separation of the entire chromosome 1 top arm territories. Homozygous transgenic tandem repeat (lac operator) arrays showing somatic homologous pairing more often than average euchromatic loci did not promote an increased frequency of sister-chromatid alignment. The high frequency of separated sister-chromatid arm positions in ≥4C nuclei suggests that sister-chromatid cohesion is variable, dynamic, and not obligatory along the entire chromosome arm in meristematic and differentiated Arabidopsis nuclei.
- Subjects
SISTER chromatid exchange; ENDOPOLYPLOIDY; ARABIDOPSIS; CHROMOSOMES; METHYLATION; GENETICS
- Publication
Genetics, 2006, Vol 172, Issue 1, p467
- ISSN
0016-6731
- Publication type
Article
- DOI
10.1534/genetics.105.048363