The glandular epithelial cells of the endometrium manifest distinct and different morphology during the different phases of the menstrual cycle. The differences may involve many hormones and are regulated by many genes. In our laboratory, we have identified the specific gene, NUDT9 (Nucleoside diphosphate-linked moiety X motif 9), expressed in the early proliferative phase or in the secretory phase. In this study we focused on the function and expression of NUDT9 protein. NUDT9 gene functions as a highly specific ADP-ribose (ADPR) pyrophosphatase. The human NUDT9 gene has been mapped to 4q22 and shown to give rise to two alternatively spliced mRNAs, the NUDT9α and NUDT9β, encoding a member of the Nudix hydrolase family. First we performed sequencing on the NUDT9 gene we identified, purified this 33 kDa protein with Ni-NTA, and then used this protein to immunize the rabbit to obtain the polyclonal antibody. We found that NUDT9 protein is differentially expressed in the endometrial gland cell by immunohistochemical stain. Besides, NUDT9 was found to express much more prominently in the endometrial carcinoma cells when compared with the surrounding non-cancer cells. According to the immunofluorescence stain of the three cell lines (A549、Huh7、HUVEC) with the assistance of confocal microscopy, we further demonstrated this protein is expressed in both the cytoplasm and nucleus, suggests that NUDT9 is expressed in cell cycle progression(S phase of DNA synthesis), and subsequently promotes the cellular proliferation. However, the exact mechanism was still largely unknown, and awaits future study.
