NCBI Summary:
Neurofilaments are type IV intermediate filament heteropolymers composed of light, medium, and heavy chains. Neurofilaments comprise the axoskeleton and functionally maintain neuronal caliber. They may also play a role in intracellular transport to axons and dendrites. This gene encodes the heavy neurofilament protein. This protein is commonly used as a biomarker of neuronal damage and susceptibility to amyotrophic lateral sclerosis (ALS) has been associated with mutations in this gene. [provided by RefSeq, Oct 2008]
General function
Cytoskeleton
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Cellular localization
Cytoskeleton
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Ovarian function
Oocyte maturation
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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
Oocyte
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The Involvement of Neurofilament Heavy Chain Phosphorylation in the Maturation and Degeneration of Rat Oocytes. Takahashi N et al. Neurofilaments (NF) are intermediate filament proteins that were originally found to be expressed in neurons and are involved in the maintenance of axonal structure. However, there has not been much research on the expression and physiological significance of NF in other organs. In the present study, we examined the expression of NF in rat ovaries and found that NF heavy chain (NF-H) was expressed in oocytes of follicles from the primary to mature stages, ovulated oocytes, fertilized zygotes, and degenerative oocytes of atretic follicles. Cytoplasmic NF-H disappeared at the two-cell stage of embryonic development, whereas degenerative oocytes of atretic follicles continued to express NF-H even after fragmentation. An antibody that specifically recognizes phosphorylated NF-H (pNF-H) was used to examine the pattern of NF-H phosphorylation in oocytes. pNF-H was detected in the cytoplasm and nuclei of oocytes of mature and atretic follicles, ovulated oocytes, and one-cell zygotes. Treatment with 3,3'-iminodipropionitrile, which induces aberrant phosphorylation of NF in the perikarya of neurons and causes neuropathy, induced oocyte degeneration with follicular atresia, phosphorylation of NF-H in oocytes, and ovarian gene expression of cyclin-dependent kinase 5, a candidate kinase of NF-H. However, an indicator of neuron degeneration, Fluoro-Jade C, failed to stain the pNF-H-immunopositive oocytes. Our results indicate that NF-H expressed in oocytes may be involved in the maintenance of oocyte structure during follicular growth and that the phosphorylation of NF-H in ephemeral oocytes may contribute to the degeneration process of oocytes.