We isolated a rat cDNA encoding part of the β-isotype of the B regulatory subunit (BRß) of protein phosphatase 2A (PP2A). The isolated cDNA encoded the region corresponding to amino acids positions 8(R) to 177(N) of human BRß. The identities of the nucleotide and amino acid sequences of the rat and human BRßs were 95.7% and 100%, respectively. The BRß mRNA was specifically expressed in rat brain and testis, the lengths of mRNAs in these two organs being different. In the testis, the BRß mRNA was first detected 40 days after birth, increasing gradually thereafter, and was expressed specifically in elongated spermatids, while mRNA of the α-isotype (BRα) was expressed equally in all spermatogenic cells. After meiosis, round spermatids change morphologically to elongated spermatids. BRß may regulate the activity of the PP2A catalytic subunit in spermatids, and be involved in spermatogenic maturation, especially spermatid elongation. © 1993.
Hatano, Y., Shima, H., Haneji, T., Miura, A. B., Sugimura, T., & Nagao, M. (1993). Expression of PP2A B regulatory subunit β isotype in rat testis. FEBS Letters, 324(1), 71–75. https://doi.org/10.1016/0014-5793(93)81535-8