VIKING - IDENTIFICATION AND CHARACTERIZATION OF A 2ND-TYPE-IV COLLAGEN IN DROSOPHILA

We have taken an enhancer trap approach to identify genes that are exp ressed in hematopoietic cells and tissues of Drosophila. We conducted a molecular analysis of two P-element insertion strains that have repo rter gene expression in embryonic hemocytes, strain 197 and viking(ICO ). This analysis has determined that viking encodes a collagen type IV gene, alpha 2(IV). The viking locus is located adjacent to the previo usly described DCg1, which encodes collagen alpha 1(IV), and in the op posite orientation. The alpha 2(IV) and alpha 1(IV) collagens are stru cturally very similar to one another, and to vertebrate type TV collag ens. In early development, viking and DCg1 are transcribed in the same tissue-specific pattern, primarily in the hemocytes and fat body cell s. Our results suggest that both the alpha 1 and alpha 2 collagen IV c hains may contribute to basement membranes in Drosophila. This work al so provides the foundation for a more complete genetic dissection of c ollagen type IV molecules and their developmental function in Drosophi la. (C) 1997 Elsevier Science B.V.