Identification and characterization of carrot HAP factors that form a complex with the embryo-specific transcription factor C-LEC1.
C-LEC1, an orthologue of Arabidopsis LEC1, is thought to be an essential transcriptional activator required for normal development during the early and late phases of embryogenesis. C-LEC1 is similar in sequence to the HAP3 subunits of other organisms. To understand C-LEC1 function better, a cDNA library of carrot somatic embryos was screened for factors that form complexes with C-LEC1. Two carrot HAP5 homologues and two carrot HAP2 homologues were identified; these factors have significant sequence similarity to the conserved regions of HAP5 and HAP2, respectively. Some of these proteins form heterotrimeric complexes that bind specifically to DNA fragments containing a CCAAT sequence in vitro. The results suggest that C-LEC1 is a component of the CCAAT-box-binding factor and forms a complex with C-HAP2B and C-HAP5A or C-HAP5B that regulates gene expression during carrot embryo development.
Yazawa
Katsumi
K
Gene Research Center, Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Ten-noudai, Tsukuba, Ibaraki 305-8572, Japan. yazawa@sakura.cc.tsukuba.ac.jp
Kamada
Hiroshi
H
D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D018552:Daucus carota / Q000196:embryology* / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D010940:Plant Proteins