| Abstrakt: |
We have identified a novel a integrin subunit in Drosophila, that associates with bPS integrin. We report the temporal expression of the gene encoding this integrin subunit, which we have called aPS3, throughout development and the localization of its expression during embryogenesis. aPS3 RNA was localized to tissues undergoing invagination, tissue movement and morphogenesis such as salivary gland, trachea, midgut, dorsal vessel, midline of the ventral nerve cord, amnioserosa and the amnioproctodeal invagination. aPS3 DNA localized to the chromosomal vicinity of scab (scb), previously identified by a failure of dorsal closure. Embryos homozygous for the l19 allele of scb had no detectable aPS3 RNA and the 1035 allele of scb contains a P element inserted just 5¢ of the coding region for the shorter of the gene’s two transcripts. Furthermore, mutations in the scb locus exhibit additional defects corresponding to sites of aPS3 transcription, including abnormal salivary glands, mislocalization of the pericardial cells and interrupted trachea. Removal of both maternal and zygotic bPS produced similar defects, indicating that these two integrin subunits associate in vivo and function in the movement and morphogenesis of tissues during development in Drosophila. Phenotypic similarities suggest that laminin A is a potential ligand for this integrin, at least in some tissues. |
