Cytosolic epoxide hydrolase is distinguished from the microsomal form (132810) by substrate specificity, molecular weight, and immunologic reactivity.
NCBI Summary:
This gene encodes a member of the epoxide hydrolase family. The protein, found in both the cytosol and peroxisomes, binds to specific epoxides and converts them to the corresponding dihydrodiols. Mutations in this gene have been associated with familial hypercholesterolemia. Alternate transcriptional splice variants of this gene have been observed but have not been thoroughly characterized.
General function
Metabolism, Enzyme, Hydrolase
Comment
Cellular localization
Cytoplasmic
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Ovarian function
Ovulation
Comment
A novel ovary-specific and ovulation-associated variant of epoxide hydrolase 2. Shkolnik K et al. Ovulation is a complex process initiated by the surge of the pituitary luteinizing hormone (LH) that provokes the expression of specific genes. We report herein the isolation and characterization of an ovulation-associated, ovary-specific novel isoform of epoxide hydrolase 2 (Ephx2), Ephx2C. This variant is exclusively expressed in the granulosa cells of preovulatory mouse ovarian follicles. The LH-induced expression of Ephx2C is mediated by the protein kinase A and partially by the protein kinase C signaling pathways. The involvement of p38 kinase has also been demonstrated.
Expression regulated by
LH
Comment
Ovarian localization
Granulosa, Luteal cells
Comment
Identification and Characterization of an Ovary-Selective Isoform of Epoxide Hydrolase Hennebold JD, et al .
A novel ovary-selective gene was identified by Suppression Subtractive Hybridization (SSH) that is expressed only during the mouse periovulatory phase of a stimulated estrous cycle. Analysis of the protein encoded by the full-length cDNA revealed that the majority of it, with the exception of the first 44 amino acids, matched soluble epoxide hydrolase (Ephx2, referred to as Ephx2A). By comparing the cDNA sequence of this newly identified variant of soluble epoxide hydrolase (referred to as Ephx2B) with the mouse genome database, an exon was identified that corresponds to its unique 5' cDNA sequence. Through the use of an Ephx2A specific probe, Northern blot analysis revealed that this mRNA was also expressed in the ovary, with the highest level of expression occurring during the luteal phase of a stimulated estrous cycle. In situ hybridization revealed that Ephx2B mRNA expression was restricted to granulosa cells of pre-ovulatory follicles. Ephx2A mRNA expression, however, was detectable in follicles at different stages of development, as well as in the corpus luteum (CL). Total ovarian epoxide hydrolase activity increased following the induction of follicular development, and remained elevated through the periovulatory and post-ovulatory stages of a stimulated estrous cycle. The change in enzyme activity paralleled the combined mRNA expression profiles for both Ephx2A and Ephx2B, thus supporting a role for epoxide metabolism in ovarian function.
Changes in mouse granulosa cell gene expression during early luteinization. McRae RS et al. Changes in gene expression during granulosa cell luteinization have been measured using serial analysis of gene expression (SAGE). Immature normal mice were treated with pregnant mare serum gonadotropin (PMSG) or PMSG followed, 48 h later, by human chorionic gonadotropin (hCG). Granulosa cells were collected from preovulatory follicles after PMSG injection or PMSG/hCG injection and SAGE libraries generated from the isolated mRNA. The combined libraries contained 105,224 tags representing 40,248 unique transcripts. Overall, 715 transcripts showed a significant difference in abundance between the two libraries of which 216 were significantly down-regulated by hCG and 499 were significantly up-regulated. Among transcripts differentially regulated, there were clear and expected changes in genes involved in steroidogenesis as well as clusters of genes involved in modeling of the extracellular matrix, regulation of the cytoskeleton and intra and intercellular signaling. The SAGE libraries described here provide a base for functional investigation of the regulation of granulosa cell luteinization.