Cloning and characterization of a Brassica napus gene encoding a homologue of the B subunit of a heteromeric CCAAT-binding factor.
The CCAAT motif present in the promoter of several genes is recognized in yeast and animals by a highly specific heteromeric factor (variously called HAP, CBF, CP1 or NF-Y) which is composed of a minimum of three subunits. A plant homologue of the CBF-B/HAP2 subunit is described for the first time in this report. Sequence comparison of the Brassica napus (Bn) CCAAT-binding factor (CBF) B subunit with the homologous yeast and animal proteins revealed that the critical amino-acid domains involved in DNA binding and subunit assembly are also conserved in plants. Interestingly, the Gln-rich regions found in the animal and yeast proteins, which may be involved in transcriptional activation, are absent in the Bn CBF-B subunit. The analysis of various cDNAs and of a genomic clone revealed the presence of alternatively spliced transcripts which could originate from different promoters.
Albani
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Plant Research Centre, Central Experimental Farm, Ottawa, Ontario, Canada.
Robert
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D017398:Alternative Splicing; D001483:Base Sequence; D001937:Brassica / Q000235:genetics*; D023081:CCAAT-Binding Factor; D022762:CCAAT-Enhancer-Binding Proteins; D003001:Cloning, Molecular; D017931:DNA Primers / Q000737:chemistry; D018076:DNA, Complementary / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics*; D005656:Fungal Proteins / Q000235:genetics*; D017343:Genes, Plant; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D015183:Restriction Mapping; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000235:genetics*
D023081:CCAAT-Binding Factor; D022762:CCAAT-Enhancer-Binding Proteins; D017931:DNA Primers; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D014157:Transcription Factors