Pineda-Santaella A, Fernández-Castillo N, Jiménez-Martín A, Macías-Cabeza MDC, Sánchez-Gómez Á, Fernández-Álvarez A. Loss of kinesin-8 improves the robustness of the self-assembled spindle in Schizosaccharomyces pombe.
J Cell Sci 2021;
134:271184. [PMID:
34346498 PMCID:
PMC8435293 DOI:
10.1242/jcs.253799]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 07/19/2021] [Indexed: 11/30/2022] Open
Abstract
Chromosome segregation in female meiosis in many metazoans is mediated by acentrosomal spindles, the existence of which implies that microtubule spindles self-assemble without the participation of the centrosomes. Although it is thought that acentrosomal meiosis is not conserved in fungi, we recently reported the formation of self-assembled microtubule arrays, which were able to segregate chromosomes, in fission yeast mutants, in which the contribution of the spindle pole body (SPB; the centrosome equivalent in yeast) was specifically blocked during meiosis. Here, we demonstrate that this unexpected microtubule formation represents a bona fide type of acentrosomal spindle. Moreover, a comparative analysis of these self-assembled spindles and the canonical SPB-dependent spindle reveals similarities and differences; for example, both spindles have a similar polarity, but the location of the γ-tubulin complex differs. We also show that the robustness of self-assembled spindles can be reinforced by eliminating kinesin-8 family members, whereas kinesin-8 mutants have an adverse impact on SPB-dependent spindles. Hence, we consider that reinforced self-assembled spindles in yeast will help to clarify the molecular mechanisms behind acentrosomal meiosis, a crucial step towards better understanding gametogenesis.
Summary: We report a comparative analysis of self-assembled spindles and canonical centrosomal spindles in fission yeast, which could clarify the mechanisms underlying acentrosomal meiosis.
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