PURIFICATION AND CELLULAR LOCALIZATION OF BETA(2)-MICROGLOBULIN IN THE TESTIS

摘要

Using multiple high performance liquid chromatography (HPLC) steps a protein of 12 kDa was purified to apparent homogeneity from rat Sertoli cell-enriched culture medium (SCCM). Partial N-terminal amino acid sequence analysis revealed a sequence of NH2-IQKTPQIQVYS which is identical to beta(2)-microgrobulin (beta(2)MG) previously identified in the brain. Studies by sequential reverse transcription and polymerase chain reaction (RT-PCR) indicated that beta(2)MG mRNA was expressed in Sertoli but not in gen cells suggesting that Sertoli cells are the source of this protein in the seminiferous epithelium behind the blood-testis barrier. The steady-state beta(2)MG mRNA level in Sertoli cells cultured in vine was not affected by either follicle stimulating hormone (FSH), testosterone, estradiol, dexamethasone or several cytokines such as interleukin-1 beta (IL-1 beta), interleukin 6 (IL-6), and transforming growth factor beta(TGF-beta), with the exception of interferon-gamma (INF gamma) which induced a dose-dependent stimulation of beta(2)MG mRNA. The possible physiological significance of this protein in the male reproductive tract is discussed. [References: 28]