Okadaic acid (OA) causes meiotic progression and chromosome condensation in cultured
pachytene spermatocytes and an increase in maturation promoting factor (cyclin B1/cdc2
kinase) activity, as evaluated by H1 phosphorylative activity in anti-cyclin B1
immunoprecipitates. OA also induces a strong increase of phosphorylative activity toward
the mitogen-activated protein kinase substrate myelin basic protein (MBP).
Immunoprecipitation experiments with anti-extracellular signal-regulated kinase 1 (ERK1) or …