PgmNr D1454: Identification of transcriptional regulators and enhancer regions of the Alk locus in Drosophila.

Authors:
P. Mendoza-Garcia 1,2 ; F. Hugosson 1 ; K. Hens 3 ; K. Pfeifer 1 ; G. Wolfstetter 1 ; D. Popichenko 2 ; B. Deplancke 4 ; R. Palmer 1


Institutes
1) Sahlgrenska Academy, Gothenburg University, Gothenburg, Sweden; 2) Molecular Biology, Umea University, Umea, Sweden; 3) Centre for Neural Circuits and Behaviour, University of Oxford, Oxford, United Kingdom; 4) Laboratory of Systems Biology and Genetics, Lausanne, Switzerland.


Keyword: core promoters and general transcription factors

Abstract:

Specification of the Drosophila visceral trunk mesoderm occurs upon inductive signals from the ectoderm. This induces the transcription of some key regulators for visceral muscle differentiation such as Tinman, Bagpipe and/or Biniou. The receptor tyrosine kinase (RTK) Alk is expressed in the developing CNS but predominantly in the embryonic trunk visceral mesoderm (VM), where is activated in response to the secreted ligand Jelly Belly (Jeb). Jeb/Alk signalling is responsible for founder cell (FC) specification in the forming VM and for the subsequent fusion to the fusion competent myoblasts (FCMs) to form the functional larval midgut. In this study we have investigated the transcriptional control Alk expression in the embryonic VM. The Alk locus was examined by several approaches including functional enhancer activity in vivo, deletion analysis, yeast one-hybrid screening and in silico analysis of predicted transcription factors binding sites. Furthermore, we have studied in vivo relevance of several identified and in silico-predicted transcription factors that could modulate Alk gene expression by single or combinatorial effect. Here we describe the identification of cis-regulatory elements in the Alk gene active during early embryogenesis and sufficient for the embryonic expression of Alk gene in the VM. This regulatory region is highly conserved among different Drosophila species. We also show the role of some of the identified transcription factors and their potential regulation of Alk transcription during embryo development through the identified regulatory region.



Flybase Genetic Index:
1. FlyBase gene symbol: Alk; FBgn: FBgn0040505