Uch-l1 And Its Associated Protein Ptov1 Follicle Development

Ubiquitin carboxyl-terminal hydrolase L1 widely expressed in mammal neurons, testes, ovaries and placentas. In order to explore the mechanism of tUCH-Ll in toad oocyte maturation, it was performed that the distribution patterns, expression levels and association with oocyte maturation of tUCH-L1 at high temperature and low temperature eggs by immunochemistry analysis, In high temperature full-grown oocytes, it was found that tUCH-L1 distributed in oocyte nucleus with a intense density; but in low temperature full-grown oocytes it concentrated in the cytoplasmic periphery close to plasma membrane. The protein content of p34cdc2,the catalytic subunit of MPF, was markedly lower in high-temperature eggs than in low temperature eggs, while no significant difference was found between the two kinds of eggs in cyclin B1. Compared with LTE-oocytes, tUCH-L1 protein content in HTE-oocytes displayed a drop to a certain degree. Cyclin B1 could be pulled out by recombinant tUCH-L1 only from mature LTE-oocyte protein extracts. And p34cdc2 corresponding bands were absorbed out specifically by recombinant tUCH-L1 from LTE-oocyte protein extracts, though the bands much thinner for immature oocytes. Accordingly, it could be deduced that environmental temperature may affect the binding of tUCH-L1 and p34cdc2, which possibly plays an important role in toad oocyte maturation.In order to further reveal the mechanism of UCH-Ll regulating follicular development, the mass spectrometry analysis was performed to screen the proteins probably interacting with UCH-L1 in mouse ovarian protein extracts. And four candidate proteins were found, there are C790407, Spnb2, PTOV1 and P140. There was an interacting association between UCH-Ll and PTOV1 substantiated by GST-UCH-L1 pull down and immunofluorescence colocalization analysis in mouse ovaries. UCH-L1 and PTOV1 co-localized in oocytes in different follicular developmental stages. Moverover, intense positive signal was detected in oocyte cytoplasmic membrane and nucleus. So it was concluded that UCH-Ll may bind with PTOV1 in oocyte cytoplasmic membrane or nucleus to play corresponding distinct biological roles.PTOV1 (prostate tumor overexpressed 1) was first identified as an overexpressed gene in prostate cancer. It was reported that PTOV1 was associated with cell cycle regulation in carcinogenesis and regarded as a potential marker for studying the carcinogenesis and progression of prostate cancer. So far, no study was reported on PTOV1 existance in mouse ovary. So, we first clarified the tissue distribution patterns in protein and mRNA levels for PTOV1 here and before for UCH-L1 in mouse ovaries. Furthermore, we discovered that estradiol affected expression levels of PTOV1. In mice, follicle cells secreted a small amount of estrogen during prepuberty, and estrogen secretion increased sharply under the control of hypothalamus-pituitary-gonadal axis to accelerate follicular development up to sex maturation. It was indicated that PTOV1 mainly localized in oocyte nuclei and granular cell cytoplasma at different follicular developmental stages, while no positive staining was detected in granular cell nuclei and theca cells. Significant positive signals were found in mouse oocyte nuclei and cytoplasmic membrane after estradiol treatment, while no or weak signals were detected in oocyte cytoplasmic membrane without estradiol treatment. But in adults, PTOV1 positive signal was detected in both the oocyte nucleus and cytoplasmic membrane. The distribution pattern in oocyte cytoplasmic membrane suggested a new mechanism of PTOV1 involvement in mouse oocyte maturation. PTOV1 and UCH-L1 protein in ovaries were shown to increase with mouse age from postnatal one to eight week. While PTOV1 and UCH-L1 mRNA levels showed no significant changes tendency with age.To sum up, the dependence of oocyte maturation competence on environmental temperature may be implicated in the association between tUCH-L1 and p34cdc2, though temperature receptors and relay within toad oocytes are still not clear. UCH-L1 and PTOV1, and their association, may contribute to estradiol functions in mouse oocyte development and maturation.