NCBI Summary:
The product of this gene is a membrane-associated protein that colocalizes with huntingtin. This protein has similarities to cytoskeleton proteins and its interaction with huntingtin is thought to play a functional role in the cell filament network. Loss of normal huntingtin-HIP1 interaction in Huntington disease may contribute to a defect in membrane-cytoskeletal integrity in the brain. This gene could help in the understanding of the normal function of huntingtin and also the pathogenesis of Huntington disease. It also has been implicated in the pathogenesis of hematopoietic malignancies. An alternative splice variant of this gene has been described but its full length sequence has not been determined.
General function
Intracellular signaling cascade, Cytoskeleton
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Cellular localization
Plasma membrane, Cytoskeleton
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Ovarian function
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Expression regulated by
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Polycystic ovary syndrome (PCOS) affects 5% of reproductive aged women and is the leading cause of anovulatory infertility. A hallmark of PCOS is excessive theca cell androgen secretion, which is directly linked to the symptoms of PCOS. Our previous studies demonstrated that theca cells from PCOS ovaries maintained in long term culture persistently secrete significantly greater amounts of androgens than normal theca cells, suggesting an intrinsic abnormality. Furthermore, previous studies suggested that ovarian hyperandrogenemia is inherited as an autosomal dominant trait. However, the genes responsible for ovarian hyperandrogenemia of PCOS have not been identified. In this present study, Wood JR, et al carried out microarray analysis to define the gene networks involved in excess androgen synthesis by the PCOS theca cells in order to identify candidate PCOS genes. Analysis revealed that PCOS theca cells have a gene expression profile that is distinct from normal theca cells. Included in the cohort of genes with increased mRNA abundance in PCOS theca cells were aldehyde dehydrogenase 6 and retinol dehydrogenase 2, which play a role in all-trans-retinoic acid biosynthesis and the transcription factor GATA6. We demonstrated that retinoic acid and GATA6 increased the expression of 17alpha-hydroxylase, providing a functional link between altered gene expression and intrinsic abnormalities in PCOS theca cells. Thus, the analyses have 1) defined a stable molecular phenotype of PCOS theca cells, 2) suggested new mechanisms for excess androgen synthesis by PCOS theca cells, and 3) identified new candidate genes that may be involved in the genetic etiology of PCOS. This is one of the genes with Altered mRNA Abundance in PCOS Theca Cells as compared with normal theca cells Maintained Under Basal Conditions.
Ovarian localization
Theca
Comment
Wijgerde M, et al reported hedgehog signaling in mouse ovary: Ihh and Dhh from granulosa cells induce target gene expression in developing theca cells.
Follicle development in the mammalian ovary requires interactions between the oocyte, granulosa cells, and theca cells, co-ordinating gametogenesis and steroidogenesis. Here, we show that granulosa cells of growing follicles in mouse ovary act as a source of hedgehog signaling. Expression of indian hedgehog (Ihh) and desert hedgehog (Dhh) mRNAs initiates in granulosa cells at the primary follicle stage, and we find induced expression of the hedgehog target genes Ptch1 and Gli1, in the surrounding pre-theca cell compartment. Cyclopamine, a highly specific hedgehog signaling antagonist, inhibits this induced expression of target genes, in cultured neonatal mouse ovaries. The theca cell compartment remains a target of hedgehog signaling throughout follicle development, showing induced expression of the hedgehog target genes Ptch1, Ptch2, Hip1, and Gli1. In peri-ovulatory follicles, a dynamic synchrony between loss of hedgehog expression and loss of induced target gene expression is observed. Oocytes are unable to respond to hedgehog, since they lack expression of the essential signal transducer Smo (smoothened). The present results point to a prominent role of hedgehog signaling in the communication between granulosa cells and developing theca cells.