The N-terminal half of the Drosophila Rel/NF-kappa B factor Relish, REL-68, constitutively activates transcription of specific Relish target genes

• The Rel/NF-kappa B transcription factor Relish is a major regulator of the antimicrobial response in Drosophila. Upon immune challenge, Relish is cleaved to generate two fragments, the DNA-binding transcription factor REL-68 and the I kappa B-like REL-49. Using transgenic fly strains we show here that overexpression of REL-68 separately from REL-49 is sufficient to activate strong constitutive transcription of the Diptericin gene, but little constitutive or inducible transcription of Attacin and Cecropin, two other Relish target genes. Their transcription may therefore require additional modifications of Relish. However, phosphorylation of the conserved serine residue S431 is not involved in such modifications. This is unlike p65 and Dorsal, which are modulated by phosphorylation at their homologous site. In contrast to other I kappa B proteins, overexpression of REL-49 had no inhibitory effect on Relish-dependent transcription. Instead, we propose that the C-terminal I kappa B-like domain executes a scaffolding and recruiting function for full activation of Relish.

Subject headings

NATURVETENSKAP  -- Biologi -- Biokemi och molekylärbiologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Biochemistry and Molecular Biology (hsv//eng)

Keyword

Innate immune response

Rel homology domain

I kappa B-like

Phosphorylation

Caspase cleavage

Scaffolding

Compound Rel protein

Antimicrobial peptide gene

Molecular biology

Molekylärbiologi

Publication and Content Type

ref (subject category)

art (subject category)