Isolation and characterization of the dopa decarboxylase gene of Drosophila melanogaster.

Abstract

We have isolated chromosomal deoxyribonucleic acid clones containing the Drosophila dopa decarboxylase gene. We describe an isolation procedure which can be applied to other nonabundantly expressed Drosophila genes. The dopa decarboxylase gene lies within or very near polytene chromosome band 37C1-2. The gene is interrupted by at least one intron, and the primary mode of regulation is pretranslational. At least two additional sequences hybridized by in vivo ribonucleic acid-derived probes are found within a 35-kilobase region surrounding the gene. The developmental profile of ribonucleic acid transcribed from one of these regions differs from that of the dopa decarboxylase transcript.The dopa decarboxylase (DDC) gene of Drosophila melanogaster is of considerable interest for a study of gene regulation. It is a well-characterized genetic locus, and it displays a complex pattern of developmental expression which is hormonally regulated during at least part of the life cycle. We have initiated a study of the structure and expression of this gene using recombinant deoxyribonucleic acid (DNA) techniques.DDC is an essential enzyme in the pathway of sclerotinization, the process of cuticle tanning and hardening in Drosophila. It is localized primarily in the hypoderm. DDC activity is developmentally regulated, showing major peaks at the time of puparium formation and again at adult eclosion (22, 26). The first major peak of enzyme activity parallels a rise in titer of the molting hormone , B-ecdysone (16, 20), and the available evidence suggests that 8i-ecdysone is required for the appearance of this enzymatic activity (20,25). In contrast, the second major peak of activity, at adult eclosion, is not correlated with an elevated f8-ecdysone titer. This activity, which occurs some 90 h after pupariation, occurs when ,B-ecdysone levels are very low and have been low for some 40 h (16). Thus, the two major inductions of DDC activity appear to be induced by dissimilar mechanisms.The

Exon skipping by overexpression of a Drosophila heterogeneous nuclear ribonucleoprotein in vivo.

“…The ratio of the aberrant AD splice form to normal Ddc mRNA is higher in the hypoderm than in the CNS. This could be explained by the normal induction of Ddc expression in the hypoderm during the third-instar larval development, in contrast to constant Ddc transcription in the CNS (28,39,40). Alternatively, the Ddc CNS mRNA could be more stable than the hypodermal mRNA, so that more normal Ddc CNS mRNAs would be retained in the CNS during this time period.…”

“…2B). We analyzed splicing of the endogenous Ddc primary transcript by reverse transcription-linked PCR, using primers specific for Ddc exons A and D. Since Ddc transcription is induced in the hypoderm during the late third-instar larval stage (28), and the CNS consists of a small portion of the body mass, the hypodermal splice form (ACD) is the predominant Ddc mRNA in these larvae. The Ddc hypodermal splicing specificity is selectively affected by heat shock, so that the endogenous Ddc CNS mRNA is found in the hypoderm during heat shock (30).…”

“…We tested whether overexpression of HRB98DE affects splice site choice of the endogenous dopa decarboxylase (Ddc) premRNA (28). The Ddc pre-mRNA is expressed primarily in the central nervous system (CNS) and the hypoderm, and it is alternatively spliced in these two tissues (29).…”

Gene Expression During Drosophila Wing Morphogenesis and Differentiation

“…This well-characterized gene is known to function in the epidermis for the crosslinking of cuticle and in the formation of melanin (Hirsh and Davidson 1981;Konrad and Marsh 1987;Wright 1996). Loss of Ddc function results in fragile and pale cuticle with thin bristles.…”

A neuron-specific enhancer of the Drosophila dopa decarboxylase gene.

“…Relevant DNA fragments were subcloned from the cloned Ddc gene of the wild-type Canton-S strain of D. melanogaster (Hirsh and Davidson 1981) and from D. virilis into M13 vectors for sequencing on both strands. Homology analyses were performed using Intelligenetics, Inc., programs accessed via BIONET.…”