Biomedical subjects

V Pantesco

Publications and source records attributed to V Pantesco.

9 recordsLinked to original sources

PubMed1993

Drosophila shaggy kinase and rat glycogen synthase kinase-3 have conserved activities and act downstream of Notch.

During neurogenesis in Drosophila, groups of equipotential, neurally competent cells choose between epidermal and neural fates. Notch, a phylogenetically conserved transmembrane protein, may act as a receptor in a lateral signalling pathway in which a single neural precursor is chosen from each group and the neural fate of the other cells is inhibited, causing them to differentiate into epidermis. Possible intracellular transduction events mediating signals from Notch are, however, unknown. shaggy is also required for the lateral signal and encodes serine/threonine protein kinases with homology to the glycogen synthase kinase-3 (GSK-3) enzymes that act in signal transduction pathways in vertebrates. We report here that, in transgenic flies, GSK-3 beta can substitute for shaggy, and we also present a study of epistatic relationships between shaggy and gain and loss of function alleles of Notch. The results indicate that shaggy/GSK-3 is part of a signalling pathway downstream of Notch.

Animals↗

PubMed1993

Functional significance of a family of protein kinases encoded at the shaggy locus in Drosophila.

The characterization of the structurally complex gene shaggy is presented. This gene encodes multiple proteins with putative serine/threonine kinase activity thought to be involved in signal transduction mechanisms that take place during several patterning events throughout Drosophila development. The gene comprises two transcription units that give rise to 10 transcripts and five different proteins with a common kinase catalytic domain and overlapping patterns of expression during development. Mutational analysis of shaggy defines a single complementation group, lethality of which is associated with the loss of two major shaggy proteins. These studies allow the first definition of a true null allele. Two proteins may fulfill maternal requirements. Phenotypes of flies expressing individual shaggy proteins revealed that although there is some redundancy between the different forms they do not all carry out identical functions in vivo. However, under experimental conditions, a single form of the protein was able to carry out all known requirements. This protein probably also functions as part of a signal transduction cascade in the imaginal neuroepithelium, where cells have to choose between epidermal and neural fates.

Age Factors↗

PubMed1988

Role of the oocyte nucleus in determination of the dorsoventral polarity of Drosophila as revealed by molecular analysis of the K10 gene.

In Drosophila, the establishment of dorsoventral polarity of the developing embryo depends on the expression of at least 11 maternally acting genes. Mutant females that lack any of these gene activities produce normally shaped eggs that develop into dorsalized embryos. The female sterile K10 mutation differs from these mutants, because in addition to the dorsalized development of the embryo, it causes a dorsalization of the egg shape. During oogenesis, the K10 gene is specifically expressed in the oocyte. Antibodies raised against a beta-galactosidase-K10 fusion protein were used to visualize the K10 product in ovaries by indirect immunofluorescence. The protein, which contains a putative DNA recognition helix, accumulates in the nucleus of the oocyte, where it is assumed to have a regulatory function. Our results thus indicate that the controlled expression of some of the genes of the oocyte nucleus is essential for the determination of the dorsoventral polarity of the oocyte and possibility of the developing embryo.

Amino Acid Sequence↗

PubMed1986