Media Mitotic Spindle Biology Diagrams Common mitotic spindle defects. Monopolar spindle induced by kinesin-5 inhibition (10 ฮผm STLC, 90 min) in hTERT RPE-1 cell (a). Prometaphase hTERT RPE-1 cell (same cell as Fig. 1b) with spindle axis oriented perpendicularly to the substrate (b). Images of the two focal planes in which the spindle poles resided are shown in the MT column. A guide to classifying mitotic stages and mitotic defects in fixed cells Nicolaas C. Baudoin1 & Daniela Cimini1 Received: 14 November 2017/Revised: 7 January 2018 /Accepted: 8 January 2018/Published online: 6 February 2018 mitotic spindle and will constitute the two spindle poles. Fig. 1 Diagrammatic representation of a mitotic cell in Correct alignment of the mitotic spindle during cell division is crucial for cell fate determination, tissue organization, and development. Mutations causing brain diseases and cancer in humans and mice have been associated with spindle orientation defects.
In this article, we provide guidelines for identifying specific mitotic stages and for classifying normal and deviant mitotic phenotypes. We hope this will clarify confusion about how certain defects are classified and help investigators avoid misnomers, misclassification, and/or misinterpretation, thus leading to a unified and standardized
Transient defects of mitotic spindle geometry and chromosome ... Biology Diagrams
A major contributor to this coordination is the mitotic spindle checkpoint. As detailed in another contribution in this series, defects in mitotic spindle assembly and chromosome alignment activate the spindle checkpoint, which delays cells in M phase. Optimally this delay allows the recovery of the normal spindle and balanced chromosome
Abnormal mitotic spindle geometry: permanent vs. transient. The bipolar geometry of the mitotic spindle is essential for accurate chromosome segregation, and already a century ago Theodor Boveri postulated that supernumerary centrosomes could lead to the production of aneuploid cells [23,24].Observations of mitosis in both transformed and non-transformed cells reveal that multipolar mitotic In general, lagging chromosomes could be generated by various mechanisms; for example, merotelic attachments (where a single kinetochore attaches to microtubules from opposite spindle poles) would generate lagging chromosomes involving single chromatids, 37 while defects in either sister chromatid resolution or removal of sister chromatid
Mitotic spindle (DIS)orientation and DISease: Cause or consequence? Biology Diagrams
impacts mitotic spindle pole integrity. This includes release of MT minus-ends from the centrosome, leading to PCM dispersion and centriole mis-posi-tioning at the spindle poles. Mechanistically, we show that these defects result from abnormal spin-dle MT dynamics due to defective kinetochore-MT attachments. Importantly, restoring mitotic spindle
