Expression and localization of MYH11 in mouse tissues, oocytes and preimplantation embryos

Myosin heavy chain 11 (MYH11), a member of the myosin family, is an actin-based cytoskeletal motor protein. Limited previous studies have revealed that the Myh11 gene is expressed in cumulus cells, cumulus-oocyte complexes, and ovarian theca cells. However, its expression profiles in mouse tissues, oocytes and preimplantation embryos are largely unknown. Here, we found that the MYH11 protein was expressed in multiple mouse tissues. In the ovary, the MYH11 protein was highly expressed in oocytes and smooth muscle fiber cells. After ovulation and fertilization, Myh11 mRNA expression had sharply declined in zygotes and could not be detected from 8-cell to blastocyst stages, while the protein persisted until the blastocyst stage. Furthermore, the MYH11 protein was localized in the cytoplasm of oocytes and preimplantation embryos. These results provide the first evidence that MYH11 is enriched in oocytes and early embryos and might play a key role in oogenesis and early embryogenesis of mice.