17 research outputs found

    Functional Characterization and Localization of the \u3ci\u3eAspergillus nidulan\u3c/i\u3e Formin SEPA

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    Formins are a family of multidomain scaffold proteins involved in actin-dependent morphogenetic events. In Aspergillus nidulans, the formin SEPA participates in two actin-mediated processes, septum formation and polarized growth. In this study, we use a new null mutant to demonstrate that SEPA is required for the formation of actin rings at septation sites. In addition, we find that a functional SEPA::GFP fusion protein localizes simultaneously to septation sites and hyphal tips, and that SEPA colocalizes with actin at each site. Using live imaging, we show that SEPA localization at septation sites and hyphal tips is dynamic. Notably, at septation sites, SEPA forms a ring that constricts as the septum is deposited. Moreover, we demonstrate that actin filaments are required to maintain the proper localization pattern of SEPA, and that the amino-terminal half of SEPA is sufficient for localization at septation sites and hyphal tips. In contrast, only localization at septation sites is affected by loss of the sepH gene product. We propose that specific morphological cues activate common molecular pathways to direct SEPA localization to the appropriate morphogenetic site

    Functional Characterization and Localization of the \u3ci\u3eAspergillus nidulan\u3c/i\u3e Formin SEPA

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    Formins are a family of multidomain scaffold proteins involved in actin-dependent morphogenetic events. In Aspergillus nidulans, the formin SEPA participates in two actin-mediated processes, septum formation and polarized growth. In this study, we use a new null mutant to demonstrate that SEPA is required for the formation of actin rings at septation sites. In addition, we find that a functional SEPA::GFP fusion protein localizes simultaneously to septation sites and hyphal tips, and that SEPA colocalizes with actin at each site. Using live imaging, we show that SEPA localization at septation sites and hyphal tips is dynamic. Notably, at septation sites, SEPA forms a ring that constricts as the septum is deposited. Moreover, we demonstrate that actin filaments are required to maintain the proper localization pattern of SEPA, and that the amino-terminal half of SEPA is sufficient for localization at septation sites and hyphal tips. In contrast, only localization at septation sites is affected by loss of the sepH gene product. We propose that specific morphological cues activate common molecular pathways to direct SEPA localization to the appropriate morphogenetic site

    The \u3ci\u3eAspergillus nidulans sepA\u3c/i\u3e gene encodes an FH1/2 protein involved in cytokinesis and the maintenance of cellular polarity

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    Cytokinesis (septation) in the fungus Aspergillus nidulans occurs through the formation of a transient actin ring at the incipient division site. Temperature-sensitive mutations in the sepA gene prevent septation and cause defects in the maintenance of cellular polarity, without affecting growth and nuclear division. The sepA gene encodes a member of the growing family of FH1/2 proteins, which appear to have roles in morphogenesis and cytokinesis in organisms such as yeast and Drosophila Results from temperature shift and immunofluorescence microscopy experiments strongly suggest that sepA function requires a preceding mitosis and that sepA acts prior to actin ring formation. Deletion mutants of sepA exhibit temperature-sensitive growth and severe delays in septation at the permissive temperature, indicating that expression of another gene may compensate for the loss of sepA. Conidiophores formed by sepA mutants exhibit abnormal branching of the stalk and vesicle. These results suggest that sepA interacts with the actin cytoskeleton to promote formation of the actin ring during cytokinesis and that sepA interacts with the actin cytoskeleton to promote formation of the actin ring during cytokinesis and that sepA is also required for maintenance of cellular polarity during hyphal growth and asexual morphogenesis

    MesA, a Novel Fungal Protein Required for the Stabilization of Polarity Axes in \u3ci\u3eAspergillus nidulans\u3c/i\u3e

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    The Aspergillus nidulans proteome possesses a single formin, SepA, which is required for actin ring formation at septation sites and also plays a role in polarized morphogenesis. Previous observations imply that complex regulatory mechanisms control the function of SepA and ensure its correct localization within hyphal tip cells. To characterize these mechanisms, we undertook a screen for mutations that enhance sepA defects. Of the mutants recovered, mesA1 causes the most dramatic defect in polarity establishment when SepA function is compromised. In a wild-type background, mesA1 mutants undergo aberrant hyphal morphogenesis, whereas septum formation remains unaffected. Molecular characterization revealed that MesA is a novel fungal protein that contains predicted transmembrane domains and localizes to hyphal tips. We show that MesA promotes the localized assembly of actin cables at polarization sites by facilitating the stable recruitment of SepA. We also provide evidence that MesA may regulate the formation or distribution of sterol-rich membrane domains. Our results suggest that these domains may be part of novel mechanism that directs SepA to hyphal tips

    Adherence to practice guidelines for atypical glandular cells on cervical cytology.

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    BACKGROUND: Atypical glandular cells (AGC) on cervical cytology are high-risk, requiring an extensive evaluation. Compliance with practice guidelines for AGC, however, has been low. Some AGC cytology reports contain cytopathologist recommendations for evaluation. This study determines whether evaluation rates for AGC have improved over time, and whether cytopathologists\u27 recommendations correlate with the types of evaluation women receive. METHODS: Evaluation rates from 284 women with AGC (2004-2007) were compared with findings from 1998-2001. Rates of evaluations were compared based on cytology report recommendations. RESULTS: A total of 76.1% of the AGC cases had histologic sampling, and 58.8% had a comprehensive evaluation. These rates are higher than those from 1998-2001 (63.5% and 35.8%, respectively; P CONCLUSIONS: Adherence to practice guidelines for the evaluation of women with AGC has improved but continues to be suboptimal. Our findings suggest that continuing education and including practice guidelines on AGC cytology reports may improve compliance

    MesA, a Novel Fungal Protein Required for the Stabilization of Polarity Axes in Aspergillus nidulans

    No full text
    The Aspergillus nidulans proteome possesses a single formin, SepA, which is required for actin ring formation at septation sites and also plays a role in polarized morphogenesis. Previous observations imply that complex regulatory mechanisms control the function of SepA and ensure its correct localization within hyphal tip cells. To characterize these mechanisms, we undertook a screen for mutations that enhance sepA defects. Of the mutants recovered, mesA1 causes the most dramatic defect in polarity establishment when SepA function is compromised. In a wild-type background, mesA1 mutants undergo aberrant hyphal morphogenesis, whereas septum formation remains unaffected. Molecular characterization revealed that MesA is a novel fungal protein that contains predicted transmembrane domains and localizes to hyphal tips. We show that MesA promotes the localized assembly of actin cables at polarization sites by facilitating the stable recruitment of SepA. We also provide evidence that MesA may regulate the formation or distribution of sterol-rich membrane domains. Our results suggest that these domains may be part of novel mechanism that directs SepA to hyphal tips

    ASCCP Committee Opinion: Adjuvant Human Papillomavirus Vaccine for Patients Undergoing Treatment for Cervical Intraepithelial Neoplasia

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    OBJECTIVES: Individuals treated for cervical intraepithelial neoplasia grade 2 or worse (CIN2+) are at long-term risk of persistent or recurrent disease despite treatment. This committee opinion aims to summarize and provide evidence-based recommendations for adjuvant human papillomavirus (HPV) vaccination based on available, published literature. METHODS: A task force from the ASCCP Practice Committee reviewed current Centers for Disease Control and Prevention (CDC) guidelines and previously published literature about the role of adjuvant HPV vaccination in previously unvaccinated individuals undergoing treatment for CIN2+ and other HPV-related diseases. RESULTS: Current CDC guidelines recommend routine or catch-up HPV vaccination for individuals aged 9 to 26 years, and shared decision making regarding vaccination for individuals aged 27 to 45 years. Multiple published studies suggest a possible benefit for adjuvant HPV vaccination in previously unvaccinated individuals undergoing treatment for CIN2+. CONCLUSIONS: The American Society for Colposcopy and Cervical Pathology recommends adherence to current CDC recommendations for vaccination of individuals aged 9 to 26 years and consideration of the possible benefit of adjuvant HPV vaccination during shared decision making for previously unvaccinated individuals aged 27 to 45 years who are undergoing treatment for CIN2+
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