Browsing by Author "Rocha, Helder"
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- Dissecting the sensory defects of bbs mutants in Caenorhabditis elegansPublication . Vitória, Filipa; Rocha, Sónia; Rocha, Helder; Abreu, Carla M. C.; Dantas, Tiago J.Ciliopathies encompass a group of genetic disorders affecting multiple organs due to dysfunction in cilia: highly conserved organelles found in most human cells. Bardet-Biedl Syndrome (BBS) is a rare ciliopathy characterized by multisystem abnormalities. BBS arises from defects in assembly, composition, or localization of the BBSome, a conserved eight-subunit protein complex crucial in ciliary transport. Sensory neurons rely on cilia to detect environmental stimuli and transduce signals essential for perception. In BBS, defective cilia function disrupts these processes, leading to impaired sensory responses. Despite advances in BBS genetics, the role of ciliary defects in sensory neuron dysfunction remains unclear. To address this gap, we utilize Caenorhabditis elegans as a model organism to dissect the sensory impairments associated with BBS mutations. Unlike mammalian systems, C. elegans can survive severe ciliary dysfunction, making it ideal for studying BBS mutations. We analyzed bbs-1 mutants to investigate sensory defects in ciliated neurons, conducting behavioral assays to assess responses to environmental stimuli, and dye-filling assay to evaluate ciliary integrity. Preliminary findings indicate disruptions in sensory neuron function, correlating with defects in ciliary morphology. Additionally, defective dye uptake in bbs-1 mutants suggests compromised ciliary integrity. Our findings emphasize the importance of ciliary function in sensory processing in C. elegans, reinforcing the role of BBS genes in ciliary integrity. The defects in sensory behavior and ciliary morphology lay the groundwork for further studies on BBS mutations.
- Prevenção do Cancro Cervical - O caso angolanoPublication . Andrade, P.; Silva, Regina Augusta; Rocha, Helder; Silva, ReginaO cancro cervical é a principal causa de mortalidade por cancro em Angola, colocando sérios desafios ao sistema de saúde do país. Esta situação resulta de deficiências nas infraestruturas de saúde pública, sensibilização da população e acesso a cuidados de saúde preventivos, apesar da disponibilidade de intervenções com boa relação custo-eficácia, como a vacinação contra o HPV e o rastreio do colo do útero. A implementação de programas de rastreio organizado é desafiante em contextos com poucos recursos, mesmo com a aplicação de métodos de inspeção visual, estes enfrentam limitações na precisão e cobertura diagnóstica. Similarmente, campanhas de vacinação contra o HPV, embora promissoras, são limitadas por barreiras sociogeográficas e logísticas. Esta revisão explora a situação atual da prevenção do cancro cervical em Angola, identificando os principais desafios, como a falta de estudos epidemiológicos, infraestruturas de rastreio e as barreiras socioeconómicas no acesso aos cuidados de saúde. Há ainda um trabalho considerável pela frente para cumprir a estratégia da Organização Mundial de Saúde para 2030 -90% de cobertura vacinal, 70% de rastreio e 90% de tratamento. No entanto, podem ser feitos progressos com a adoção de métodos de rastreio inovadoras que incluam a auto-amostragem e unidades de saúde móveis, expandindo esforços de vacinação e reduzindo obstáculos culturais e logísticos.
- ZYG-12/Hook's dual role as a dynein adaptor for early endosomes and nuclei is regulated by alternative splicing of its cargo binding domainPublication . Carvalho, Cátia; Moreira, Matilde; Barbosa, Daniel J.; Chan, Fung-Yi; Koehnen, Carlota Boal; Teixeira, Vanessa; Rocha, Helder; Green, Mattie; Carvalho, Ana Xavier; Cheerambathur, Dhanya K.; Gassmann, RetoThe microtubule motor cytoplasmic dynein-1 transports and positions variousorganelles, but the molecular basis of this functional diversity is not fully understood. Cargoadaptors of the Hook protein family recruit dynein to early endosomes (EE) in fungi andhuman cells by forming the FTS–Hook–FHIP (FHF) complex. By contrast, the Caenorhabdi-tis elegans Hook homologue ZYG-12 recruits dynein to the nuclear envelope (NE) in themeiotic gonad and mitotic early embryo by forming a Linker of Nucleoskeleton and Cy-toskeleton (LINC) complex. Here, we demonstrate that ZYG-12 recruits dynein to EE inepithelia. We identify and functionally characterize the homologues of FTS (UBC-19) andFHIP (FHIP-1) that constitute the C. elegans FHF complex, validate the predicted FHIP-1–RAB-5 binding interface in vivo, and show that ZYG-12 forms FHF via a conserved segmentthat precedes, and is distinct from, its C-terminal NE targeting domain. Finally, we showthat C-terminal ZYG-12 splice isoforms differ in their ability to target to the NE and EE.We conclude that the C. elegans Hook adaptor evolved to recruit dynein to two distinctorganelles, and that cargo specificity of ZYG-12 is regulated by alternative splicing.