Analysis of the amplification and transcription of the C3-22 gene of Rhynchosciara americana (Diptera: Sciaridae) in transgenic lines of Drosophila melanogaster

Abstract

Drosophila melanogaster was transformed with an 18 kb fragment of the C3 DNA puff of Rhynchosciara americana, including the C3-22 gene and the origins of replication that direct amplification. Different tissues and developmental stages of five independent transgenic lines were analyzed by quantitative Southern blot hybridization. No indication was found that the transformed fragment was amplified, strongly suggesting that factors involved in DNA puff amplification have not been conserved in Drosophila. Transcription of the C3-22 gene in the transgenic lines was found to be at a low and constitutive level throughout development. These results indicate that, unlike other DNA puff genes, the factors that regulate the C3-22 gene are not conserved in Drosophila.

Intrinsically bent DNA in replication origins and gene promoters

“…Gene amplification provides a useful model for studying the replication origin structure and the control of the initiation replication. The models that have been studied most involve chromosomes that contain the chorion genes of Drosophila melanogaster (Claycomb and Orr-Weaver, 2005) and DNA puffs of sciarid flies, such as Rhynchosciara americana (Yokosawa et al, 1999;Soares et al, 2003). In Rhynchosciara americana, multiple bent DNA sites were found in the replication origin encompassing the C3-22 gene (Fiorini et al, 2006a).…”

Intrinsic Bent DNA Sites in the Developmentally AmplifiedC3-22Gene Promoter ofRhynchosciara americana(Diptera: Sciaridae)

“…Drosophila melanogaster transgenic lineages for the C3-22, BhC4-1, and BhB10 genes are available [53][54][55] and might be useful in such studies.…”

Amplification and expression of a salivary gland DNA puff gene in the prothoracic gland of Bradysia hygida (Diptera: Sciaridae)

“…Functional studies revealed that the mechanisms that regulate DNA amplification in sciarid DNA puffs are not conserved in Drosophila, which has hampered the characterization of both the cis-regulatory elements and trans-activating factors that control the amplification of DNA puff genes (Bienz-Tadmor et al, 1991;Monesi et al, 1998Monesi et al, , 2001Soares et al, 2003). Nevertheless, the mechanisms that regulate expression of DNA puff genes have been shown to be conserved in the case of the II/9-1 gene of S. coprophila and the BhC4-1 gene of B. hygida (Bienz-Tadmor et al, 1991;Monesi et al, 1998).…”