Molecular cloning and characterization of Bombyx mori CREB gene

Authors


  • ATF

    activating transcription factor

    bZIP

    basic region/leucine zipper

    BmCREB

    cAMP response element binding protein of Bombyx mori

    CBP

    CREB binding protein

    CREB

    cAMP response element binding protein

    CREM

    cAMP response element modulator

    DH

    diapause hormone

    DL-condition

    darkness and low temperature condition

    LW-condition

    light and warm temperature condition

    KID

    kinase-inducible domain

    PCR

    polymerase chain reaction

    RT- PCR

    reverse-transcribed polymerase chain reaction

    SG

    suboesophageal ganglion

    UTR

    untranslated region

Abstract

The cAMP response element binding protein (CREB), as one of the best characterized stimulus-induced transcription factors, plays critical roles in activating transcription of target genes in response to a variety of environmental stimuli. To characterize this important molecule in the silkworm, Bombyx mori, we cloned a full-length cDNA of CREB gene from B. mori brains by using RACE-PCR. The sequence of B. mori CREB (named BmCREB1) gene contains a 88 bp 5′ UTR, a 783 bp open reading frame (ORF) encoding 261 amino acids and a 348 bp 3′ UTR. The deduced BmCREB amino acid sequence has 56.7% and 37.2% homology with CREB from Apis mellifera carnica and Drosophila melanogaster, respectively. The primary structure of the deduced BmCREB1 protein contains a kinase-inducible domain (KID) and a basic region/leucine zipper (bZIP) dimerization domain which exisits in all CREB family members. Genomic analysis showed there are 9 exons and 5 introns in B. mori CREB genome sequences. We identified three different isoforms of BmCREB (BmCREB1, BmCREB2 and BmCREB3) through alternative splicing in C terminal. In addition, the expression of BmCREB in different developmental stages was investigated by using quantitative real-time PCR in both diapause and non-diapause type of B. mori bivoltine race (Dazao). BmCREB transcripts showed two peaks in embryonic stage and pupal stage in both types of bivoltine race. However, consistently higher expression of BmCREB was found throughout the developmental stages in the diapause type than in the non-diapause type. These results suggest that BmCREB is involved in the processs of diapause induced by environmental factors. © 2009 Wiley Periodicals, Inc.

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