Author(s):
Lopes, Catarina Teixeira 
Date: 2008
Persistent ID: http://hdl.handle.net/10451/1222
Origin: Repositório da Universidade de Lisboa
Subject(s): Embriologia; Biologia evolutiva; Teses de mestrado
Document details
Cell-extrallular matrix interactions during early paraxial mesoderm development
Description
Tese de mestrado, Biologia (Biologia Evolutiva e do Desenvolvimento), 2007, Universidade de Lisboa, Faculdade de Ciências Fibronectin is an abundant glycoprotein of the extracellular matrix, which has been shown to play a role in a variety of functions such as cell proliferation, survival, migration and differentiation. Fibronectin is assembled into a fibrillar matrix through a cell-mediated process involving their heterodimeric membrane receptors, integrins. Recently, the work of our group has evidenced the importance of fibronectin in somitogenesis and how the ectoderm and mesoderm collaborate in the construction of the fibronectin matrix of presomitic mesoderm (Rifes et al., 2007). In the present work, we further characterised the expression patterns of fibronectin (Fn1), integrin α5 (Itga5), the main sub-unit involved in fibronectin assembly, and integrin α4 (Itga4), during chick embryonic development. Fn1 transcripts are strongly expressed in most epithelia, mainly in the ectoderm in all stages studied. Itga5 is initially expressed in the primitive streak and node and it is later found in the ingressing mesoderm and many of its derivates, especially the heart and vascular primordia. Itga4 transcripts are also detected in the node and mesoderm, but later it is expressed in the dorsal neural tube and somite derivates. Finally, we also established an in vitro culture system of presomitic mesoderm cells by using different enzymes and substrata. Immunofluorescence labelling of fibronectin shows that isolated PSM cells in culture can assembly a fibronectin matrix, even when it was previously removed by dispase. In the tested culture conditions, these cells remained in a non-proliferative mesenchymal-like state, expressing very low levels of both N-cadherin and ß-catenin. These data suggest that fibronectin is not only an important component of the extracellular matrix in vivo and in vitro, but also that its presence in various tissues during the early stages of chick development is imperative
Tese de mestrado, Biologia (Biologia Evolutiva e do Desenvolvimento), 2007, Universidade de Lisboa, Faculdade de Ciências Fibronectin is an abundant glycoprotein of the extracellular matrix, which has been shown to play a role in a variety of functions such as cell proliferation, survival, migration and differentiation. Fibronectin is assembled into a fibrillar matrix through a cell-mediated process involving their heterodimeric membrane receptors, integrins. Recently, the work of our group has evidenced the importance of fibronectin in somitogenesis and how the ectoderm and mesoderm collaborate in the construction of the fibronectin matrix of presomitic mesoderm (Rifes et al., 2007). In the present work, we further characterised the expression patterns of fibronectin (Fn1), integrin α5 (Itga5), the main sub-unit involved in fibronectin assembly, and integrin α4 (Itga4), during chick embryonic development. Fn1 transcripts are strongly expressed in most epithelia, mainly in the ectoderm in all stages studied. Itga5 is initially expressed in the primitive streak and node and it is later found in the ingressing mesoderm and many of its derivates, especially the heart and vascular primordia. Itga4 transcripts are also detected in the node and mesoderm, but later it is expressed in the dorsal neural tube and somite derivates. Finally, we also established an in vitro culture system of presomitic mesoderm cells by using different enzymes and substrata. Immunofluorescence labelling of fibronectin shows that isolated PSM cells in culture can assembly a fibronectin matrix, even when it was previously removed by dispase. In the tested culture conditions, these cells remained in a non-proliferative mesenchymal-like state, expressing very low levels of both N-cadherin and ß-catenin. These data suggest that fibronectin is not only an important component of the extracellular matrix in vivo and in vitro, but also that its presence in various tissues during the early stages of chick development is imperative
Document Type
Master Thesis
Advisor(s) Rodrigues, Maria Gabriela
Advisor(s) Rodrigues, Maria Gabriela
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