Arabidopsis CHROMOSOME TRANSMISSION FIDELITY 7 (AtCTF7/ECO1) is required for DNA repair, mitosis and meiosis.
Bottom Line: No significant change was observed in the expression of genes that influence entry into the endocycle.Analysis of meiocytes identified changes in chromosome morphology and defective segregation; the abundance of chromosomal-bound cohesion subunits was also reduced.Taken together our results demonstrate that Arabidopsis CTF7/ECO1 plays important roles in the preservation of genome integrity and meiosis.
Affiliation: Institute of Plant and Microbial Biology, Academia Sinica, Taipei, 11529, Taiwan.Show MeSH
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Mentions: In order to obtain direct evidence of the role of Arabidopsis CTF7/ECO1 in mitotic chromosome segregation, root tips were excised from 2-week-old seedlings corresponding to WT, Com, ctf7-1 and ctf7-2. As observed in Figure 8, it was possible to observe cell division from interphase to telophase. In both WT and Com, 10 chromocenters were observed during interphase (Figure 8a,e), which corresponds to a diploid number of chromosomes, while in ctf7-1 (Figure 8i) and ctf7-2 (Figure 8m) the chromocenters often appeared decondensed and in some cases an excess of 10 chromocenters was observed. During metaphase, WT (Figure 8b) and Com (Figure 8f) cells typically displayed 10 condensed chromosomes; however, chromosomes in cells of ctf7-1 (Figure 8j) and ctf7-2 (Figure 8n) appeared less condensed and irregularly shaped. At anaphase, WT (Figure 8c) and Com (Figure 8g) cells showed even segregation of chromosomes, and individual chromosomes could be recognized, while chromosomes in cells of ctf7-1 (Figure 8k) and ctf7-2 (Figure 8o) looked intertwined and stretched, and condensation was defective. In telophase, WT (Figure 8d) and Com (Figure 8h) cells showed segregation of chromosomes into two well-condensed masses of equal size, but in ctf7-1 (Figure 8l) and ctf7-2 (Figure 8p) chromosome bridges persisted and the chromosomes often recondensed into a single unevenly shaped mass of DNA (Figure 8l,p). In fact chromosome segregation in homozygous ctf7-1 and ctf7-2 mitotic cells is statistically different from WT (P < 0.001, Student's t-test) and shows defective chromosome segregation (Figure 8q). Taken together these results suggest that CTF7/ECO1 plays a critical role in the regulation of chromosome segregation during mitotic cell division.
Affiliation: Institute of Plant and Microbial Biology, Academia Sinica, Taipei, 11529, Taiwan.