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R Bodner

Publications and source records attributed to R Bodner.

5 recordsLinked to original sources
PubMed2000

The enhancer of split complex of Drosophila includes four Notch-regulated members of the bearded gene family.

During Drosophila development, transcriptional activation of genes of the Enhancer of split Complex (E(spl)-C) is a major response to cell-cell signaling via the Notch (N) receptor. Although the structure and function of the E(spl)-C have been studied intensively during the past decade, these efforts have focused heavily on seven transcription units that encode basic helix-loop-helix (bHLH) repressors; the non-bHLH members of the complex have received comparatively little attention. In this report, we analyze the structure, regulation and activity of the m1, m2 and m6 genes of the E(spl)-C. We find that E(spl)m2 and E(spl)m6 encode divergent members of the Bearded (Brd) family of proteins, bringing to four (m(alpha), m2, m4 and m6) the number of Brd family genes in the E(spl)-C. We demonstrate that the expression of both m2 and m6 is responsive to N receptor activity and that both genes are apparently direct targets of regulation by the N-activated transcription factor Suppressor of Hairless. Consistent with this, both are expressed specifically in multiple settings where N signaling takes place. Particularly noteworthy is our finding that m6 transcripts accumulate both in adult muscle founder cells in the embryo and in a subset of adepithelial (muscle precursor) cells associated with the wing imaginal disc. We show that overexpression of either m2 or m6 interferes with N-dependent cell fate decisions in adult PNS development. Surprisingly, while misexpression of m6 impairs lateral inhibition, overexpression of m2 potentiates it, suggesting functional diversification within the Brd protein family. Finally, we present our initial studies of the structure, expression and regulation of the newest member of the Brd gene family, Ocho, which is located in the recently identified Bearded Complex.

Amino Acid Sequence↗
PubMed2000

Antagonism of notch signaling activity by members of a novel protein family encoded by the bearded and enhancer of split gene complexes.

Cell-cell signaling through the Notch receptor is a principal mechanism underlying cell fate specification in a variety of developmental processes in metazoans, such as neurogenesis. In this report we describe our investigation of seven members of a novel gene family in Drosophila with important connections to Notch signaling. These genes all encode small proteins containing predicted basic amphipathic (&agr;)-helical domains in their amino-terminal regions, as described originally for Bearded; accordingly, we refer to them as Bearded family genes. Five members of the Bearded family are located in a newly discovered gene complex, the Bearded Complex; two others reside in the previously identified Enhancer of split Complex. All members of this family contain, in their proximal upstream regions, at least one high-affinity binding site for the Notch-activated transcription factor Suppressor of Hairless, suggesting that all are directly regulated by the Notch pathway. Consistent with this, we show that Bearded family genes are expressed in a variety of territories in imaginal tissue that correspond to sites of active Notch signaling. We demonstrate that overexpression of any family member antagonizes the activity of the Notch pathway in multiple cell fate decisions during adult sensory organ development. These results suggest that Bearded family genes encode a novel class of effectors or modulators of Notch signaling.

3' Untranslated Regions↗
PubMed1997

A multivalent PDZ-domain protein assembles signalling complexes in a G-protein-coupled cascade.

How are signalling molecules organized into different pathways within the same cell? In Drosophila, the inaD gene encodes a protein consisting of five PDZ domains which serves as a scaffold to assemble different components of the phototransduction cascade, including the principal light-activated ion channels, the effector phospholipase C-beta and protein kinase C. Null inaD mutants have a dramatically reorganized subcellular distribution of signalling molecules, and a total loss of transduction complexes. Also, mutants defective in a single PDZ domain produce signalling complexes that lack the target protein and display corresponding defects in their physiology. A picture emerges of a highly organized unit of signalling, a 'transduclisome', with PDZ domains functioning as key elements in the organization of transduction complexes in vivo.

Amino Acid Sequence↗