Colchicine-induced polyploidization depends on tubulin polymerization in c-metaphase cells

Abstract

The microtubule cytoskeleton plays a crucial role in the cell cycle and in mitosis. Colchicine is a microtubule-depolymerizing agent that has long been used to induce chromosome individualization in cells arrested at metaphase and also in the induction of polyploid plants. Although attempts have been made to explain the processes and mechanisms underlying polyploidy induction, the role of the cytoskeleton still remains largely unknown. Through immunodetection of alpha-tubulin, different concentrations (0.5 or 5 mM) of colchicine were found to produce opposite effects in the organization of the cytoskeleton in rye (Secale cereale L.). A low concentration (0.5 mM) induced depolymerization of the microtubular cytoskeleton in all phases of the cell cycle. In contrast, a high concentration (5 mM) was found to induce the polymerization of new tubulin-containing structures in c-metaphase cells. Furthermore, both treatments also showed contrasting effects in the induction of polyploid cells. Flow cytometric analysis and quantitative assessments of nucleolus-organizing regions revealed that only the high-concentration colchicine treatment was effective in the formation of polyploid cells. Our studies indicate that spindle disruption alone is insufficient for the induction of polyploid cells. The absence of any tubulin structures in plants treated with colchicine at the low concentration induced cell anomalies, such as the occurrence of nuclei with irregular shape and/or (additional) micronuclei, 12 h after recovery, pointing to a direct effect on cell viability. In contrast, the almost insignificant level of cell anomalies in the high-concentration treatment suggests that the presence of new tubulin-containing structures allows the reconstitution of 4C nuclei and their progression into the cell cycle.

Behavior of RNAs transcripts during nucleolus assembly and disassembly in Vicia faba root meristematic cells under normal conditions and after colchicine treatment

“…In agreement with earlier observations made both on plant and animal cells (Caperta et al 2006;HernandezVerdun et al 1991), the obtained results indicate that apart from cells having regular diploid and polyploid nuclei, colchicine-induced disorganization of microtubules brought about a number of cells with aneuploid nuclei devoid of functional NORs or NORs per se. Due to significant reduction of A-type cells formed after HU treatment, it seems reasonable to suppose that they appear mostly as a result of the second round of mitosis, i.e., following nuclear division of tetraploid cells.…”

Genomic behavior of hybrid combinations between elephant grass and pearl millet

“…Preliminary results showed non-preferential chromosome elimination. The chromosome elimination process could be a consequence of the aneuploidizant effect of colchicine -an alkaloid used for chromosome doubling -, resulting in random chromosome losses (Schoenlein et al, 2003;Caperta et al, 2006).…”

Characterization of Diversity in Toxicity Mechanism Using in Vitro Cytotoxicity Assays in Quantitative High Throughput Screening

“…Interestingly, based on its being in Cluster 16, colchicine might reasonably be expected to possess micronucleus activity even though no such activity was reported in the NTP database. A search of the literature determined that colchicine, in fact, is known to be a micronucleus inducer (28,29). Another cluster, Cluster 4, was significantly enriched in estrogens and estrogen mimetics, including ethinyl estradiol, diethylstilbestrol, bisphenol A, methoxyclor, and aldrin (30).…”