Multiple genes encoding the conserved CCAAT-box transcription factor complex are expressed in Arabidopsis.
The CCAAT motif is found in the promoters of many eukaryotic genes. In yeast a single complex of three proteins, termed HAP2, HAP3, and HAP5, binds to this sequence, and in mammals the three components of the equivalent complex (called variously NF-Y, CBF, or CP1) are also represented by single genes. Here we report the presence of multiple genes for each of the components of the CCAAT-binding complex, HAP2, 3,5, from Arabidopsis. Three independent Arabidopsis HAP subunit 2 (AtHAP2) cDNAs were cloned by functional complementation of a yeast hap2 mutant, and two independent forms each of AtHAP3 and AtHAP5 cDNAs were detected in the expressed sequence tag database. Additional homologs (two of AtHAP3 and one of AtHAP5) have been identified from available Arabidopsis genomic sequences. Northern-blot analysis indicated ubiquitous expression for each AtHAP2 and AtHAP5 cDNA in a range of tissues, whereas expression of each AtHAP3 cDNA was under developmental and/or environmental regulation. The unexpected presence of multiple forms of each HAP homolog in Arabidopsis, compared with the single genes in yeast and vertebrates, suggests that the HAP2,3,5 complex may play diverse roles in gene transcription in higher plants.
Edwards
D
D
Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, United Kingdom.
Murray
J A
JA
Smith
A G
AG
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics*; D029681:Arabidopsis Proteins; D023081:CCAAT-Binding Factor; D022762:CCAAT-Enhancer-Binding Proteins; D003001:Cloning, Molecular; D017124:Conserved Sequence; D004268:DNA-Binding Proteins / Q000235:genetics*; D005656:Fungal Proteins / Q000235:genetics; D015870:Gene Expression / Q000235:genetics; D017343:Genes, Plant / Q000235:genetics*; D005816:Genetic Complementation Test; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000235:genetics*; D010940:Plant Proteins / Q000235:genetics; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000235:genetics
D029681:Arabidopsis Proteins; D023081:CCAAT-Binding Factor; D022762:CCAAT-Enhancer-Binding Proteins; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C114160:HAP proteins, Arabidopsis; C491932:At5g12840 protein, Arabidopsis; C491933:HAP2b protein, Arabidopsis; C491934:HAP2c protein, Arabidopsis; C491930:HAP3a protein, Arabidopsis; C491935:HAP5a protein, Arabidopsis; C491936:HAP5b protein, Arabidopsis; D010940:Plant Proteins; D014157:Transcription Factors