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Identification of a cis ‐regulatory element for L1 layer‐specific gene expression, which is targeted by an L1‐specific homeodomain protein
Author(s) -
Abe Mitsutomo,
Takahashi Taku,
Komeda Yoshibumi
Publication year - 2001
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1046/j.1365-313x.2001.01047.x
Subject(s) - biology , arabidopsis , gene , genetics , homeobox , conserved sequence , arabidopsis thaliana , transcription factor , primordium , physcomitrella patens , gene expression , microbiology and biotechnology , mutant , peptide sequence
Summary The Arabidopsis thaliana PROTODERMAL FACTOR1 ( PDF1 ) gene encoding a putative extracellular proline‐rich protein is exclusively expressed in the L1 layer of shoot apices and the protoderm of organ primordia. In order to identify essential cis ‐regulatory sequences required for the L1 layer‐specific expression, a series of 5′ deletions of the PDF1 promoter were fused to the β‐ glucronidase ( GUS ) gene and introduced into Arabidopsis plants. Our analysis revealed that the minimum region necessary to confer L1‐specific expression of PDF1 is confined within a 260‐bp fragment upstream of the transcription start site. We identified an 8‐bp motif in this region that is conserved between promoter regions of all the L1‐specific genes so far cloned, and we designated it the L1 box. Electrophoretic mobility shift assays demonstrated that the L1‐specific homeodomain protein ATML1 can bind to the L1 box sequence in vitro . The GUS expression in transgenic plants disappeared when a mutation that abolishes binding of ATML1 was introduced into the PDF1 l 1 box sequence of the construct. These results suggest that the L1 box plays a crucial role in the regulation of PDF1 expression in L1 cells and that ATML1 could cooperate to drive L1‐specific expression.