SACL, a bHLH gene that restricts vascular cell proliferation in plants.
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ABSTRACT: The final size and arrangement of the plant vasculature requires precise adjustment of cell proliferation. In particular, radial growth of vascular bundles is to a large extent controlled by a bHLH transcription factor heterodimer formed by TARGET OF MONOPTEROS5 (TMO5) and LONESOME HIGHWAY (LHW). Excess activity of this TMO5/LHW dimer causes excessive proliferation of vascular cell divisions and thus suggests the existence of a molecular mechanism that restricts its activity in space and time. Here we show that this overproliferation phenotype is similar to acaulis5 (acl5) mutants, suggesting a role for ACL5 in controlling TMO5/LHW activity. We further identify the clade of SAC51-LIKE (SACL) bHLH transcription factors whose translation is regulated by ACL5, as inhibitors of TMO5/LHW activity. We show that SACL proteins interact with LHW impairing activation of downstream targets and alleviating the overproliferation caused by TMO5/LHW misexpression. Given that transcription of SACL genes is induced by TMO5/LHW and its upstream trigger auxin, we propose that SACL proteins represent a feedback mechanism that limits activity of this pathway and controls periclinal cell divisions.
ORGANISM(S): Arabidopsis thaliana
PROVIDER: GSE70157 | GEO | 2015/09/01
SECONDARY ACCESSION(S): PRJNA287768
REPOSITORIES: GEO
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