Meiosis Biology Diagrams The universal features of meiotic spindle formation have yet to be determined; nonetheless, modulation of this process by the bouquet may occur in many eukaryotes. In higher eukaryotes, meiotic spindles can be nucleated from several different structures, including centrosomes, MTOCs, and complexes of motor proteins. Centromere-telomere interchangeability in promoting meiotic spindle formation. Meiotic progression is represented from left to right. (A) In WT meiocytes, the movement of telomeres to the SPB promotes modification of Sad1 (yellow stars) or the NM surrounding Sad1, in turn promoting Sad1 accumulation and ensuring bipolar spindle formation.
Expressed throughout meiotic progression, PLK1 promotes meiotic progression and is needed for high-quality meiotic spindle formation (Pahlavan et al., 2000; Solc et al., 2015). Overall, the important role of PLK1 in oocyte meiosis, its responsiveness to exogenous and endogenous signals, and the known adverse effects of these signals on meiotic Additionally, localized protein synthesis to support spindle formation is achieved in the spindle forming region, whilst protein synthesis is reduced elsewhere in the ooplasm. This is achieved through enrichment of spindle-related mRNAs in the spindle forming region combined with local PLK1-mediated phosphorylation and inactivation of the ery—the oocyte meiotic spindle—that distinguish it from the mitotic spindle, and discuss recent progress in understanding the molecular mech-anisms that mediate spindle assembly early in oocyte meiosis I. Finally, we will review the spindle dynamics that align and segregate chromosomes later in meiosis I to produce a haploid genome. 2.
Acentriolar spindle assembly in mammalian female meiosis and the ... Biology Diagrams
Herein, we describe the recent advances in understanding the mechanisms controlling formation of the meiotic spindle in metaphase I (MI) and metaphase II (MII) in mammalian oocytes, and focus on the differences between mouse and human oocytes. Unlike mitotic cells, mammalian oocytes lack typical centrosomes that consist of two centrioles and
Although centrosome-mediated spindle formation is dominant in most mitotic cells, mitosis can still take place in the absence of centrosomes, showing that other centrosome-independent pathways can participate in spindle formation (Khodjakov et al., 2000; Basto et al., 2006; Azimzadeh et al., 2012; Bazzi and Anderson, 2014). These centrosome Kinetochore fibers are not involved in the formation of the first meiotic spindle in mouse oocytes, but control the exit from the first meiotic M phase. The Journal of Cell Biology, 146, 1-12. [PMC free article] [Google Scholar] Burbank KS, et al. (2006). A new method reveals microtubule minus ends throughout the meiotic spindle.
Meiotic spindle formation in mammalian oocytes: implications for human ... Biology Diagrams
In this review, we discuss the basics of spindle formation during oocyte meiotic maturation focusing on mouse and human studies. Finally, we review different factors that could alter the process of spindle formation and its stability. We conclude with a discussion of how different assisted reproductive technologies could affect spindles and the Meiotic spindle abnormality in human oocytes is a hallmark of maternal ageing [44], [196]. In conclusion, it is clear that there are gene products that are essential for control of spindle formation, chromosome cohesion and chromosome segregation in meiosis. These possibly present targets for chemicals that specifically interfere with
