Investigation of LAMTOR1 gene and protein expressions in germinal vesicle and metaphase II oocytes and embryos from 1-cell to blastocyst stage in a mouse model

Abstract

Improving the success of in vitro fertilization (IVF) and infertility treatment depend on understanding basic cellular and molecular mechanisms of human preimplantation development. Pre-implantation mouse embryo model is an ideal empiric system to understand these mechanisms. This study was aimed to investigate the gene and protein expressions of LAMTOR1 in mouse oocytes and pre-implantation embryos at different developmental stages. The findings demonstrate that LAMTOR1 was detected in the oocytes and in subsequent all stages of embryo development. The expression was increased progressively from MII-stage oocyte to morula stage embryo (p < 0.05), highest expression was identified in morula stage (p < 0.05), and decreased in blastocyst stage (p < 0.05). Immunofluorescence analysis showed outer and inner nuclear membranes and cytoplasmic subcellular localizations of LAMTOR1 in oocytes and pre-implantation embryos. The LAMTOR1 immunoexpression was gradually increased from MII oocyte and the highest level was detected at the morula stage of embryo development (p < 0.05). The lowest LAMTOR1 immunoexpression was detected at GV-stage oocyte (p < 0.05) and no clear difference in M2 oocyte, I-cell, 2-cell, and blastocyst stage embryos. In conclusion, both the mRNA and protein levels of LAMTOR1 increase progressively in cleavage-stage mouse embryos. LAMTOR1 has a significant higher embryonic expression at 2-cell to morula stage. LAMTOR1 may play a role in the oogenesis process and probably required for further developmental stages and it may play a possible role in the process of compaction and cavitation in mice. Therefore, further studies are needed to explore the LAMTOR1 expression especially in the different stages of embryonal development.