Full-length CDNA Cloning Of CBF/DREB1 Transcription Factor From Caragana Korshinkii Kom And Its Bioinformatics Analysis

Temperature is one of the key factors that restricts growth and distribution of plants. Extreme low temperature will hurt plants and is the major factor of crops yield reduction in the north part of China. Under cold stress, C-repeat/dehydration responsive binding factors (CBFs) are induced rapidly in higher plants, and activates all kinds of cold-resistance mechanism and expression of the cold-resisted protein to prevent the damage.In this paper, a 996bp full-length cDNA of the CBF (NtCBF) from Caragana Korshinskii Kom was cloned by degenerate RT-PCR and RACE, which includes an open reading frame of 615bp, 124bp of the 5'untranslated region, 246bp of the 3'untranslated regions, poly A signal and poly(A)11. the start codon is ATG, and the termination codon is TAA.The deduced protein has the typilcal AP2/EREBP domain, and shows significant sequence similarity with those known CBFs especially in conserved AP2/EREBP DNA-binding domain. More bioinformatics analysis showes this NtCBF belongs to the CBF family of AP2-DNA-binding protein superfamily. It has an AP2 binding region with two special sects of short polypeptides of PKK/RPAGRxKFxETRHP and DSAWR and a putative active acidic region. NtCBF has nuclear localization signal, but no signal peptide and or transmembrane structure was found.Amino acid homology analysis showed that the AP domains of the CBFs from all the dicotylons are highly conserved. AP2 of NtCBF shares 68.9%, 68.5%, 62.5% and 61.6% identity with the other four proteins GmCBF, GsCBF, MtCBF2 and MtCBF3 respectively, which all belong to the Legume family.