WHAMM is required for meiotic spindle migration and asymmetric cytokinesis in mouse oocytes

Abstract

WASP homolog associated with actin, membranes and microtubules (WHAMM) is a newly discovered nucleation-promoting factor that links actin and microtubule cytoskeleton and regulates transport from the endoplasmic reticulum to the Golgi apparatus. However, knowledge of WHAMM is limited to interphase somatic cells. In this study, we examined its localization and function in mouse oocytes during meiosis. Immunostaining showed that in the germinal vesicle (GV) stage, there was no WHAMM signal; after meiosis resumption, WHAMM was associated with the spindle at prometaphase I (Pro MI), metaphase I (MI), telophase I (TI) and metaphase II (MII) stages. Nocodazole and taxol treatments showed that WHAMM was localized around the MI spindle. Depletion of WHAMM by microinjection of specific short interfering (si)RNA into the oocyte cytoplasm resulted in failure of spindle migration, disruption of asymmetric cytokinesis and a decrease in the first polar body extrusion rate during meiotic maturation. Moreover, actin cap formation was also disrupted after WHAMM depletion, confirming the failure of spindle migration. Taken together, our data suggest that WHAMM is required for peripheral spindle migration and asymmetric cytokinesis during mouse oocyte maturation.

Methoxychlor exposure induces oxidative stress and affects mouse oocyte meiotic maturation

“…The protocol was essentially as described previously (Huang et al, ; Liu et al, ). Oocytes were fixed with 4% paraformaldehyde for 30 min, and then permeabilization with 0.5% Triton‐X 100 for 30 min.…”

Resveratrol Protects Mouse Oocytes from Methylglyoxal-Induced Oxidative Damage

“…The protocol was basically the same as described in our previous studies[23]–[25]. Oocytes were fixed with 4% paraformaldehyde for 30 min.…”

Roles of actin binding proteins in mammalian oocyte maturation and beyond

“…23 Moreover, the ARP2/3 complex is responsible for the formation of a thicker cortex region called the 'subcortex'; the formation of the subcortex by ARP2/3 may be a factor mediating the exclusion of non-muscle myosin II and can cause changes in cortex softening during oocyte maturation. 12,13 Nucleation-promoting factor (NPF) family proteins are necessary for the activation of the ARP2/3 complex, and several NPFs, including Wiskott-Aldrich syndrome protein family member 2 (WAVE2), 66 neuronal Wiskott-Aldrich syndrome protein (N-WASP), 67 junction-mediated regulatory protein (JMY), 68 WASP homolog associated with actin, membranes, and microtubules (WHAMM), 69 and WAS protein family homolog 1 (WASH), 70 are implicated in oocyte maturation (Fig. 2D).…”