Expression of stem-loop binding protein during murine oogenesis and pre-implantation development

Abstract

The goal of the work presented here was to investigate the hypothesis that cytoplasmic SLBP is required for translation of somatic H1 mRNA, and their translational repression is due to a lack of SLBP in the cytoplasm of oocytes, and early cleavage-stage embryos. To this end, the expression of SLBP in murine oocytes and pre-implantation embryos was characterized by RT-PCR, Western blotting, and immunocytochemical. techniques.mRNA encoding SLBP was detected throughout oogenesis and pre-implantation development, from small growing oocytes to the late blastocyst stage. SLBP protein was found in the nucleus and cytoplasm of growing and fully-gown prophase I-arrested oocytes. SLBP accumulated to extremely high levels during meiotic maturation in a process requiring translation. The protein remained abundant both in the nucleus and cytoplasm throughout the 1- and 2-cell stages. SLBP was depleted in 4-cell embryos in a process independent of DNA replication, and was not detected again until the late 8-cell stage. From the late 8-cell stage to the early blastocyst stage, SLBP was detected exclusively in the cytoplasm. Interestingly, in late blastocysts, SLBP was translocated to the nucleus. (Abstract shortened by UMI.