Molecular and genetic analysis of cross vein patterning in the wing of Drosophila melanogaster

The wing of Drosophila melangaster contains precisely patterned longitudinal veins (LVs) and cross veins (CVs). The LVs have been extensively studied molecularly, but no molecular analysis has focused on CVs. The CVs develop later than the LVs, and there is a group of 5 crossveinless (cv) genes that function specifically in CV development.;This thesis presents evidence for the molecular nature of crossveinless-2 (cv-2), the first cv gene to be cloned. The putative cv-2 gene product contains five adjacent cysteine-rich (CR) domains, also called von Willebrand Factor Type C (VWFc) domains. Each CR domain contains about 70 amino acids, in which the cysteines have a conserved spacing. The known patterning genes chordin (chd) and short gastrulation (sog) contain four such CRs. A region of CV-2 carboxy terminal to the CRs is highly similar to a portion of the von Willebrand Factor Type D (VWFd) domain. VWFd domains are important in cell-cell interactions, such as the formation of large extracellular protein complexes.;I show here that the cv-2 gene interacts positively in wildtype CV development with the decapentaplegic ( dpp) and the glass-bottom boat (gbb) genes. The dpp gene is known to be antagonized by the sog gene during the embryonic development of Drosophila. My data indicate that this sog gene antagonizes cv-2 during wildtype CV development. I show that the hedgehog (hh) and chicadee (chic ) genes interact with cv-2. I demonstrate that the major patterning gene wg functions in CV development, and is likely involved in the ancestral patterning of CVs.;Finally, I present the molecular structure of the 57D-E region of Chromosome II, which contains cv-2. This region, of more than 180 kb, contains previously undescribed genes. One of them, Dm-eftu, codes for ELONGATION FACTOR-TU. Also included in 57D-E are two adjacent acyl-CoEnzymeA oxidase (Dm-acox) genes. The acox gene has been studied extensively in yeasts and vertebrates. Database searching reveals that there are at least four acox genes in the Drosophila genome, and seven in the Caenorhabditis elegans genome. I survey known data regarding the role of the acox gene in fatty acid metabolism and in human disease.