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Evaluating Increases in Positive COVID-19 Tests Following Major Holidays
Is there a significant difference between the day-to-day increase in positive COVID-19 test results during the COVID-19 incubation period following a major holiday and that of a period of 2-14 days with no holidays or significant events?
Chromosome organisation during cell division and effects on nuclear shape in interphase
Abnormally shaped, lobed nuclei are often observed in cancer cells, although the mechanisms causing these misshapen nuclei are unknown. Here, the effects of chromosome organization during cell division on nuclear shape were measured as solidity (roundness). One consequence of abnormal nuclear shape is that misshapen cell nuclei may alter gene expression, dramatically shifting normal cell activity and contributing to disease. Many proteins, including the class of molecular motors, called kinesins, direct regular cell activities including cell division. The kinesin Kif18A is responsible for maintaining chromosome alignment in the middle of a dividing cell before chromosomes segregate, producing two daughter cells. Without Kif18A, chromosomes are unaligned at metaphase, causing disordered chromosome segregation. In this study, it was investigated whether proper chromosome alignment during cell division impacts the resulting nuclear shape of daughter cells. Live cells transfected with a fluorescently labeled plasmid (GFP-H2B, to label chromatin) were imaged and analyzed using the program ImageJ to observe chromosome dynamics and cell shape after division. In the absence of Kif18A, daughter cell nuclei had lower solidity measurements, meaning nuclei were more abnormally shaped (p<0.0001). Furthermore, in the absence of Kif18A, cells were more likely to have lagging chromosomes which led to the production of micronuclei (whole or fragmented chromosomes separated from the main nucleus). Additionally, population-wide, Kif18A mutants had more cells with abnormally shaped nuclei compared to the control. These results suggest that chromosome alignment during cell division impacts nuclear shape of daughter cells, and is a possible mechanism leading to abnormal nuclear shape.
Dec 5, 2020Chromosome organisation during cell division and effects on nuclear shape in interphase
Abnormally shaped, lobed nuclei are observed in cancer cells ,although the mechanisms causing the misshapen are unknown. Here the effects of chromosome organisation during cell division were measured as solidity( roundness). One consequence of abnormal nuclear shape is that misshapen cell nuclei may alter gene expression dramatically shifting normal cell activity and contributing to diseases . Many proteins including the class of molecular motors called kinesins Kif18A direct regular cell activities including cell division. The Kif18A is responsible for maintaining chromosome alignment in the middle of a dividing cell before chromosomes segregate producing two daughter cells. Without Kif18A chromosomes are unaligned at metaphase causing disordered chromosome organisation. In this study it was investigated whether proper chromosome alignment during cell division impacts the resulting nuclear shape of daughter cells. Live cells transfected with a fluorescently labelled plasmid (GFP-H2B to label chromatin) were imaged and analysed using program Image J to observe chromosome dynamics and cell shape after division. In the absence of Kif18A daughter cell nuclei had lower solidity measurements meaning nuclei were less round. Furthermore, in the absence of Kif18A cells were more likely to have lagging chromosomes which led to the production of micronuclei. Additionally population wide Kif18A mutants had more cells with abnormally shaped nuclei compared to the control. This results suggest that chromosome organisation impacts nuclear shape of daughter cells and is a possible mechanism leading to abnormal nuclear shape .
