Drosophila homolog of the mammalian jun oncogene is expressed during embryonic development and activates transcription in mammalian cells.

Abstract

By means of low-stringency cross-species hybridization to Southern DNA blots, human c-jun sequences were used to identify a unique Drosophila melanogaster locus (Djun). The predicted DJun protein is highly homologous to members of the mammalian Jun family in both the DNA binding and leucine zipper regions. Djun was mapped by in situ hybridization to position 46E of the second chromosome. It encodes a 1.7-kilobase transcript constitutively expressed at all developmental stages. Functionally, Djun in cooperation with mouse c-fos can trans-activate activator protein 1 DNA binding site when introduced into mammalian cells. Taken together, these data suggest that Djun, much like its mammalian homolog, may activate transcription of genes involved in regulation of cell growth, differentiation, and development. Furthermore, the identification of Djun allows one to exploit the genetics of Drosophila to identify genes in signal transduction pathways involving Djun and thus c-jun.

The mammalian Jun proteins: redundancy and specificity

“…Their relative abundance modulates speci®c gene transcription and engages cells in a precise destiny. The existence of di erent Jun proteins in vertebrates contrasts with the unique Jun partner yet identi®ed in Drosophila (Zhang et al, 1990;RiesgoEscovar and Hafen, 1997) or Xenopus (Knochel et al, 2000). Multi-gene family may be involved in ®ne modulation of complex processes in higher vertebrates.…”

Induction of Disease-associated Keratin 16 Gene Expression by Epidermal Growth Factor Is Regulated through Cooperation of Transcription Factors Sp1 and c-Jun

“…The existence of Drosophila c-Jun protein that is highly homologous to members of the mammalian Jun family in both the DNA binding and leucine zipper domains has been well-documented (27). Cells were transfected with either the expression vector pPacSp1 (Fig.…”

A Member of the p38 Mitogen-Activated Protein Kinase Family Is Responsible for Transcriptional Induction ofDopa decarboxylasein the Epidermis ofDrosophila melanogasterduring the Innate Immune Response

“…In Drosophila, the MAPK kinase (MAPKK), Hemipterous (HEP) (23), activates the JNK, Basket (BSK) (9), which can then phosphorylate the heterodimeric transcription factor AP-1 (40,64), which is composed of a FOS subunit and a JUN subunit (59,87). Phosphorylation activates AP-1 and causes induction of JNK response genes.…”