Identification of a target for CudA, the transcription factor which directs formation of the Dictyostelium tip organiser.
The tip of the Dictyostelium slug functions much like an embryonic organiser; when grafted onto the flank of a recipient slug, it recruits a mass of prespore cells and leads them away as part of a secondary slug. CudA is a nuclear protein which is expressed in prespore cells where it acts as a specific transcription factor. CudA is also expressed in an anteriorly located group of cells, the tip-organiser, that is believed to constitute the functional tip. We identify an expansin-like gene, expl7, that is expressed within the tip-organiser region and which is not expressed in a cudA null strain. The expl7 promoter contains a region that binds to CudA in vitro and this region is necessary for expression in the tip-organiser. These results provide an end-point for a previously defined signal transduction pathway in which regionalized expression of the ACA adenylyl cyclase within the tip-organiser leads to localised cAMP-induced activation of STATa and consequent binding of STATa to the cudA promoter. STATa then induces expression of cudA and cudA directs the transcription of target genes such as expl7.
Wang
Hong-Yu
HY
College of Life Sciences, University of Dundee, Dundee, UK.
Williams
Jeffrey G
JG
D001483:Base Sequence; D004023:Dictyostelium / Q000254:growth & development* / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D017403:In Situ Hybridization; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism*
C107317:CudA protein, Dictyostelium discoideum; D009687:Nuclear Proteins; D010940:Plant Proteins; D015800:Protozoan Proteins; C095825:expansin protein, plant