Asb7, short for ankyrin repeat and SOCS box-containing protein 7, is a gene with significant roles in multiple biological processes. It is a substrate receptor of cullin 5 Ring E3 ubiquitin ligase and is involved in ubiquitination-mediated proteasomal degradation, which impacts various cellular functions such as cytoskeletal organization, spindle dynamics, and endoplasmic reticulum (ER) stress response [2,3,4].

In mouse oocyte meiosis, ASB7-specific knockdown disrupts maturational progression and the meiotic apparatus, leading to abnormal spindle, misaligned chromosomes, loss of cortical actin cap, and increased aneuploidy. It also impairs kinetochore-microtubule interaction and activates the spindle assembly checkpoint. Moreover, ASB7 protein is reduced in oocytes from aged mice, and increasing its expression can partially rescue maternal age-induced meiotic defects [1]. In mitosis, knockdown of ASB7 in cells decreases microtubule polymerization and increases the proportion of cells with unaligned chromosomes, as it ubiquitinates DDA3, a regulator of spindle dynamics, for proteasomal degradation [3]. In HeLa cells, ER stress leads to increased ASB7 expression, but knockdown of ASB7 does not protect cells from ER stress-induced cell death and is associated with up-regulation of pro-inflammatory genes [4].

In conclusion, Asb7 is crucial for regulating cytoskeletal organization during oocyte maturation, spindle dynamics in mitosis, and response to ER stress. Studies using gene-knockdown models in mice and cells have revealed its role in these biological processes, which may have implications for understanding age-related oocyte quality decline, cell division-related disorders, and ER stress-associated diseases.