Open AccessRegulation of SHOOT MERISTEMLESS genes via an upstream-conserved noncoding sequence coordinates leaf development
Author(s) -
Naoyuki Uchida,
Brad T. Townsley,
KookHyun Chung,
Neelima Sinha
Publication year - 2007
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.0707577104
Subject(s) - primordium , meristem , biology , homeobox , gene , arabidopsis , genetics , arabidopsis thaliana , regulation of gene expression , conserved sequence , gene expression , microbiology and biotechnology , mutant , peptide sequence
The indeterminate shoot apical meristem of plants is characterized by the expression of the Class 1KNOTTED1-LIKE HOMEOBOX (KNOX1 ) genes.KNOX1 genes have been implicated in the acquisition and/or maintenance of meristematic fate. One of the earliest indicators of a switch in fate from indeterminate meristem to determinate leaf primordium is the down-regulation ofKNOX1 genes orthologous toSHOOT MERISTEMLESS (STM ) inArabidopsis (hereafter calledSTM genes) in the initiating primordia. In simple leafed plants, this down-regulation persists during leaf formation. In compound leafed plants, however,KNOX1 gene expression is reestablished later in the developing primordia, creating an indeterminate environment for leaflet formation. Despite this knowledge, most aspects of howSTM gene expression is regulated remain largely unknown. Here, we identify two evolutionarily conserved noncoding sequences within the 5′ upstream region ofSTM genes in both simple and compound leafed species across monocots and dicots. We show that one of these elements is involved in the regulation of the persistent repression and/or the reestablishment ofSTM expression in the developing leaves but is not involved in the initial down-regulation in the initiating primordia. We also show evidence that this regulation is developmentally significant for leaf formation in the pathway involvingASYMMETRIC LEAVES1/2 (AS1/2 ) gene expression; these genes are known to function in leaf development. Together, these findings reveal a regulatory point of leaf development mediated through a conserved, noncoding sequence inSTM genes.