Publicação
narcissus is required for the correct establishment of left-right asymmetries in the zebrafish brain
| Resumo: | The vertebrate brain is functionally and anatomically left-right (L-R) asymmetric, yet how these asymmetries arise and are maintained during development is still poorly understood. ln zebrafish, the epithalamus comprises some of the most conspicuous asymmetries found in vertebrates, making it a valuable model to study their development. In it left and right dorsal habenulae (dHb) develop differently in size, cytoarquitecture and axonal connectivity. Additionally, the parapineal organ migrates to the left side and exclusively projects to the left habenula (lRb), being required for the development of its molecular and subsequent cytoarchitectural left-sided identity. Several studies have shown that Nodal Wnt and Notch signalling pathways have an important role in dHb asymmetric specification. However, how they interact with each other to achieve this is still largely unknown. Through a forward genetic screen our lab has identified the narcissus mutation which induces defects in the asymmetric specification of dRb neurons. Here, we show that in narcissus mutants, both habenulae display symmetric expression of some, but not all, 1Hb markers, and that the asymmetric afferent projections to the interpeduncular nucleus (IPN) and efferent innervation from the olfactory bulb and parapineal are disrupted. Additionally, both habenulae display significantly less BrdU incorporation in two tested timepoints, but asymmetric early neurogenesis still occurs. Together, our findings demonstrate that narcissus is required for the correct specification of L-R asymmetries in the zebrafish brain and provide a valuable background for future studies to decipher its role in the establishment and maintenance of these asymmetries during embryonic development. |
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| Autores principais: | Henriques, Pedro Miguel Dias, 1989- |
| Assunto: | Biologia do desenvolvimento Cérebro Fisiologia animal Peixe-zebra Teses de mestrado - 2013 |
| Ano: | 2013 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade de Lisboa |
| Idioma: | inglês |
| Origem: | Repositório da Universidade de Lisboa |
| Resumo: | The vertebrate brain is functionally and anatomically left-right (L-R) asymmetric, yet how these asymmetries arise and are maintained during development is still poorly understood. ln zebrafish, the epithalamus comprises some of the most conspicuous asymmetries found in vertebrates, making it a valuable model to study their development. In it left and right dorsal habenulae (dHb) develop differently in size, cytoarquitecture and axonal connectivity. Additionally, the parapineal organ migrates to the left side and exclusively projects to the left habenula (lRb), being required for the development of its molecular and subsequent cytoarchitectural left-sided identity. Several studies have shown that Nodal Wnt and Notch signalling pathways have an important role in dHb asymmetric specification. However, how they interact with each other to achieve this is still largely unknown. Through a forward genetic screen our lab has identified the narcissus mutation which induces defects in the asymmetric specification of dRb neurons. Here, we show that in narcissus mutants, both habenulae display symmetric expression of some, but not all, 1Hb markers, and that the asymmetric afferent projections to the interpeduncular nucleus (IPN) and efferent innervation from the olfactory bulb and parapineal are disrupted. Additionally, both habenulae display significantly less BrdU incorporation in two tested timepoints, but asymmetric early neurogenesis still occurs. Together, our findings demonstrate that narcissus is required for the correct specification of L-R asymmetries in the zebrafish brain and provide a valuable background for future studies to decipher its role in the establishment and maintenance of these asymmetries during embryonic development. |
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