Fig. 9: Model describing the role of PBAF in spermatocyte cell division.
From: Mammalian SWI/SNF chromatin remodeler is essential for reductional meiosis in males
ARID2 expression peaks towards the end of prophase-I (diplonema), when the PBAF complex is associated with centromeres and promoters of genes known to participate in processes such as spindle assembly and nuclear division. The timely regulation of these genes is critical for the transition from metaphase-I to anaphase-I, culminating in reductional meiosis. Metaphase-I spermatocytes expressing ARID2 assemble bipolar spindle attached to meiotic bivalents (shaded blue) that display kinetochores enriched for PLK1 (purple hexagon), centromeric H3T3P/H2AT120P (magenta circle), and chromatin-associated chromosome passenger complex (CPC) (Orange circle). The loss of ARID2 results in a metaphase-I arrest due to the mis-expression of essential cell division genes. Consequently, mutants lack normal spindle and display abnormal meiotic bivalents (shaded magenta) with kinetochores devoid of PLK1 (empty hexagon), ectopic H3T3P/H2AT120P distributed chromosomally, and chromatin deficient in CPC.
