Dystroglycan (Dg) is a transmembrane receptor for laminin that must be expressed at the right time and place in order to be involved in notochord morphogenesis. The function of Dg was examined in Xenopus laevis embryos by knockdown of Dg and overexpression and replacement of the endogenous Dg with a mutated form of the protein. This analysis revealed that Dg is required for correct laminin assembly, for cell polarization during mediolateral intercalation and for proper differentiation of vacuoles.
View Article and Find Full Text PDFInvertebrate and vertebrate development relies on complex processes that require many coordinated cell functions including cell adhesion, migration, proliferation and polarization. These processes depend on tissues and are spatio-temporally regulated by specific interactions between cells and between cells and the extracellular matrices. The dystroglycan, a transmembrane receptor that binds multiple extracellular matrix proteins, is expressed from oogenesis to organogenesis.
View Article and Find Full Text PDFCell growth, proliferation, differentiation and survival are influenced by the availability of oxygen. The effect of hypoxia on embryonic cells and the underlying molecular mechanisms to maintain cellular viability are still poorly understood. In this study, we show that hypoxia during Xenopus embryogenesis rapidly leads to a significant developmental delay and to cell apoptosis after prolonged exposure.
View Article and Find Full Text PDFDystroglycan (Dg) is a transmembrane protein involved both in the assembly and maintenance of basement membrane structures essential for tissue morphogenesis, and the transmission of signals across the plasma membrane. We used a morpholino knockdown approach to investigate the function of Dg during Xenopus laevis skin morphogenesis. The loss of Dg disrupts epidermal differentiation by affecting the intercalation of multiciliated cells, deposition of laminin, and organization of fibronectin in the extracellular matrix (ECM).
View Article and Find Full Text PDFA growing body of evidence suggests that genes transcribed by RNA polymerase III exhibit multiple functions within a chromosome. While the predominant function of these genes is the synthesis of RNA molecules, certain RNA polymerase III genes also function as genomic landmarks. Transfer RNA genes are known to exhibit extra-transcriptional activities such as directing Ty element integration, pausing of replication forks, overriding nucleosome positioning sequences, repressing neighboring genes (tRNA position effect), and acting as a barrier to the spread of repressive chromatin.
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