NCBI Summary:
This gene is a homolog of the Drosophila diaphanous gene, and has been linked to autosomal dominant, fully penetrant, nonsyndromic sensorineural progressive low-frequency hearing loss. Actin polymerization involves proteins known to interact with diaphanous protein in Drosophila and mouse. It has therefore been speculated that this gene may have a role in the regulation of actin polymerization in hair cells of the inner ear. Alternatively spliced transcript variants encoding distinct isoforms have been found for this gene. [provided by RefSeq, Jul 2008]
General function
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Cellular localization
Nuclear
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Ovarian function
Early embryo development
, First polar body extrusion
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Formin mDia1, a downstream molecule of FMNL1, regulates Profilin1 for actin assembly and spindle organization during mouse oocyte meiosis. Zhang Y et al. (2015) Mammalian diaphanous1 (mDia1) is a homologue of Drosophila diaphanous and belongs to the Formin-homology family of proteins that catalyze actin nucleation and polymerization. Although Formin family proteins, such as Drosophila diaphanous, have been shown to be essential for cytokinesis, whether and how mDia1 functions during meiosis remain uncertain. In this study, we explored possible roles and the signaling pathway involved for mDia1 using a mouse oocyte model. mDia1 depletion reduced polar body extrusion, which may have been due to reduced cortical actin assembly. mDia1 and Profilin1 had similar localization patterns in mouse oocytes and mDia1 knockdown resulted in reduced Profilin1 expression. Depleting FMNL1, another Formin family member, resulted in reduced mDia1 expression, while RhoA inhibition did not alter mDia1 expression, which indicated that there was a FMNL1-mDia1-Profilin1 signaling pathway in mouse oocytes. Additionally, mDia1 knockdown resulted in disrupting oocyte spindle morphology, which was confirmed by aberrant p-MAPK localization. Thus, these results demonstrated indispensable roles for mDia1 in regulating mouse oocyte meiotic maturation through its effects on actin assembly and spindle organization.//////////////////
The Mos-MAPK pathway regulates Diaphanous-related formin activity to drive cleavage furrow closure during polar body emission in starfish oocytes. Ucar H 2013 et al.
Maintenance of spindle attachment to the cortex and formation of the cleavage furrow around the protruded spindle are essential for polar body emission (PBE) during meiotic maturation of oocytes. Although spindle movement to the cortex has been well-studied, how the spindle is maintained at the cortex during PBE is unknown. Here, we show that activation of Diaphanous-related formin mediated by mitogen-activated protein kinase (MAPK) is required for tight spindle attachment to the cortex and cleavage furrow closure during PBE in starfish (Asterina pectinifera) oocytes. A. pectinifera Diaphanous-related formin (ApDia) had a distinct localization in immature oocytes and localized to the cleavage furrow during PBE. Inhibition of the Mos-MAPK pathway or the actin nucleating activity of formin homology 2 domain prevented cleavage furrow closure and resulted in PBE failure. In MEK/MAPK-inhibited oocytes, activation of ApDia by relief of its intramolecular inhibition restored PBE. In summary, this study elucidates a link between the Mos-MAPK pathway and diaphanous-related formins, that is responsible for maintaining tight spindle attachment to the cortex and cleavage furrow closure during PBE.
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Dynamic interaction of formin proteins and cytoskeleton in mouse oocytes during meiotic maturation. Kwon S et al. Formin-2 (Fmn2) nucleates actin filaments required for spindle migration during the metaphase of meiosis I in mouse oocytes. While recent studies showed that Fmn2 is involved in the formation of a dynamic actin meshwork on meiotic spindle and the migration of chromosomes, the precise location and the mechanism of action of Fmn2 in the mouse oocyte is not known. In this work, we show that Fmn2 is colocalized with spindle during metaphase I (MI) and this pattern is lost in nocodazole-treated oocytes. Fmn2 directly interacts with polymerized microtubules in vitro via a well-conserved domain called formin homology 2 (FH2). Microinjection of mRNA encoding FH1FH2 domains of Fmn2 into Fmn2-/- oocytes partially rescued the defect of polar body extrusion, while mRNAs encoding FH2 domain alone could not rescue the defect. mDia1 and mDia2, Diaphanous (Dia) subfamily of formin proteins, exhibit unique patterns of expression in mouse oocytes. While mDia1 is localized on meiotic spindle, mDia2 localization is confined in spindle poles similar to ?-tubulin. Collectively, our results suggest that the ability of Fmn2 to directly interact with microtubules and to polymerize actins via the conserved FH1FH2 domains are crucial for chromosomal migration in MI oocytes. We also show that mDia1 and mDia2 are dynamic components of meiotic spindle and pole complex during meiotic maturation of oocytes.
Expression regulated by
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Histone deacetylase 6 (HDAC6) is an essential factor for oocyte maturation and asymmetric division in mice. Zhou D et al. (2017) Tubastatin A (Tub-A), a highly selective histone deacetylase 6 (HDAC6) inhibitor, has been widely used as a cytotoxic anticancer agent, or for the treatment of patients with asthma. However, the potential toxicity of Tub-A on oocyte maturation and asymmetric division is still unclear. Therefore, the present study was designed to examine the effect and potential regulatory role of Tub-A on the meiotic maturation of oocytes. We observed that Tub-A treatment induced an increased level of the acetylation of α-tubulin, and a failure of spindle migration and actin cap formation. Based on the spindle structure, most Tub-A treated oocytes were arrested in an MI-like or a GVBD-like stage and exhibited decondensed chromosomes in a dose dependent manner. Moreover, Tub-A treatment decreased the protein expression of mTOR, a factor responsible for spindle formation, and the expression of mDia1, an inhibitor of actin assembly, in an HDAC6 expression-dependent manner. Importantly, following Tub-A supplementation, most oocytes failed to extrude the first polar body, which indicates that these defects are closely linked to abnormal oocyte maturation. Taken together, our data demonstrates that HDAC6 is one of the essential factors for oocyte maturation and asymmetric division via the HDAC6/mTOR or mDia1 pathway in mice.//////////////////
Ovarian localization
Oocyte
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Follicle stages
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Phenotypes
Mutations
3 mutations
Species: human
Mutation name: None
type: naturally occurring fertility: fertile Comment: Nonsyndromic deafness DFNA1 associated with mutation of a human homolog of the Drosophila gene diaphanous. Lynch ED et al. The gene responsible for autosomal dominant, fully penetrant, nonsyndromic sensorineural progressive hearing loss in a large Costa Rican kindred was previously localized to chromosome 5q31 and named DFNA1. Deafness in the family is associated with a protein-truncating mutation in a human homolog of the Drosophila gene diaphanous. The truncation is caused by a single nucleotide substitution in a splice donor, leading to a four-base pair insertion in messenger RNA and a frameshift. The diaphanous protein is a profilin ligand and target of Rho that regulates polymerization of actin, the major component of the cytoskeleton of hair cells of the inner ear.
Species: mouse
Mutation name: type: null mutation fertility: unknown Comment: T cell responses in mammalian diaphanous-related formin mDia1 knock-out mice. Eisenmann KM et al. (2007) Activated T cells rapidly assemble filamentous (F-) actin networks in response to ligation of the T cell receptor or upon interaction with adhesive stimuli in order to facilitate cell migration and the formation of the immune synapse. Branched filament assembly is crucial for this process and is dependent upon activation of the Arp2/3 complex by the actin nucleation-promoting factor Wiskott-Aldrich Syndrome protein (WASp). Genetic disruption of the WAS gene has been linked to hematopoietic malignancies and various cytopenias. Although the contributions of WASp and Arp2/3 to T cell responses are fairly well characterized, the role of the mammalian Diaphanous (mDia)-related formins, which both nucleate and processively elongate non-branched F-actin, has not been demonstrated. Here, we report the effects on T cell development and function following the knock out of the murine Drf1 gene encoding the canonical formin p140mDia1. Drf1(-/-) mice develop lymphopenia characterized by diminished T cell populations in lymphoid tissues. Consistent with a role for p140mDia1 in the regulation of the actin cytoskeleton, isolated Drf1(-/-) splenic T cells adhered poorly to extracellular matrix proteins and migration in response to chemotactic stimuli was completely abrogated. Both integrin and chemokine receptor expression was unaffected by Drf1(-/-) targeting. In response to proliferative stimuli, both thymic and splenic Drf1(-/-) T cells failed to proliferate; ERK1/2 activation was also diminished in activated Drf1(-/-) T cells. These data suggest a central role for p140mDia1 in vivo in dynamic cytoskeletal remodeling events driving normal T cell responses.//////////////////
Species: D. melanogaster
Mutation name: type: null mutation fertility: infertile - ovarian defect Comment: Diaphanous is required for cytokinesis in Drosophila and shares domains of similarity with the products of the limb deformity gene. Castrillon DH et al. (1995) We show that the Drosophila gene diaphanous is required for cytokinesis. Males homozygous for the dia1 mutation are sterile due to a defect in cytokinesis in the germline. Females trans-heterozygous for dia1 and a deficiency are sterile and lay eggs with defective eggshells; failure of cytokinesis is observed in the follicle cell layer. Null alleles are lethal. Death occurs at the onset of pupation due to the absence of imaginal discs. Mitotic figures in larval neuroblasts were found to be polyploid, apparently due to a defect in cytokinesis. The predicted 123 x 10(3) M(r) protein contains two domains shared by the formin proteins, encoded by the limb deformity gene in the mouse. These formin homology domains, which we have termed FH1 and FH2, are also found in Bni1p, the product of a Saccharomyces cerevisiae gene required for normal cytokinesis in diploid yeast cells.//////////////////