Drosophila nuclear factor DREF regulates the expression of the mitochondrial DNA helicase and mitochondrial transcription factor B2 but not the mitochondrial translation factor B1

Abstract

DREF [DRE (DNA replication-related element)-binding factor] controls the transcription of numerous genes in Drosophila, many involved in nuclear DNA (nDNA) replication and cell proliferation, three in mitochondrial DNA (mtDNA) replication and two in mtDNA transcription termination. In this work, we have analysed the involvement of DREF in the expression of the known remaining genes engaged in the minimal mtDNA replication (d-mtDNA helicase) and transcription (the activator d-mtTFB2) machineries and of a gene involved in mitochondrial mRNA translation (d-mtTFB1). We have identified their transcriptional initiation sites and DRE sequences in their promoter regions. Gel-shift and chromatin immunoprecipitation assays demonstrate that DREF interacts in vitro and in vivo with the d-mtDNA helicase and d-mtTFB2, but not with the d-mtTFB1 promoters. Transient transfection assays in Drosophila S2 cells with mutated DRE motifs and truncated promoter regions show that DREF controls the transcription of d-mtDNA helicase and d-mtTFB2, but not that of d-mtTFB1. RNA interference of DREF in S2 cells reinforces these results showing a decrease in the mRNA levels of d-mtDNA helicase and d-mtTFB2 and no changes in those of the d-mtTFB1. These results link the genetic regulation of nuclear DNA replication with the genetic control of mtDNA replication and transcriptional activation in Drosophila.

Dysfunction of Drosophila mitochondrial carrier homolog (Mtch) alters apoptosis and disturbs development

“…Double‐stranded RNA (dsRNA) was designed with a sequence comprising over 200 bp of the 5′ side of Mtch mRNA. A dsRNA designed against bacterial LacZ was used as negative control [ 41 ]. Cells were treated with the dsRNA for 24 h and then divided in three sets.…”

Phosphine inhibits transcription of the catalase gene through the DRE/DREF system in Drosophila melanogaster

“…As recently reviewed by Nguyen et al ., DREF is a multifunctional factor, and could positively regulate the expression of genes other than CAT 21 . To determine whether these DREF target genes were also targets of PH 3 , we investigated the expression of seven DREF target genes including WARTS 22 , TTF 23 , TFB2 24 , HIPPO 25 , OSA 26 , MOIRA 26 , and P53 27 in S2 cells after PH 3 treatment. Our results showed that the expression of TTF and TFB2 , which are related to mitochondrial function, were partly reduced after PH 3 treatment, indicating that the DRE/DREF system might play a common role in relaying the PH 3 signal to its target genes (Fig.…”