BMB Rep. 2014; 47(2): 92-97  
Sequence-specific interaction between ABD-B homeodomain and castor gene in Drosophila
Keon-Hee Kim & Siuk Yoo*
Department of Life Sciences, College of Sciences, Yeungnam University, Gyeongsan 712-749, Korea
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Received: May 22, 2013; Revised: June 6, 2013; Accepted: June 12, 2013; Published online: February 28, 2014.
© Korean Society for Biochemistry and Molecular Biology. All rights reserved.

We have examined the effect of bithorax complex genes on the expression of castor gene. During the embryonic stages 12-15, both Ultrabithorax and abdominal-A regulated the castor gene expression negatively, whereas Abdominal-B showed a positive correlation with the castor gene expression according to real-time PCR. To investigate whether ABD-B protein directly interacts with the castor gene, electrophoretic mobility shift assays were performed using the recombinant ABD-B homeodomain and oligonucleotides, which are located within the region 10 kb upstream of the castor gene. The results show that ABD-B protein directly binds to the castor gene specifically. ABD-B binds more strongly to oligonucleotides containing two 5'-TTAT-3' canonical core motifs than the probe containing the 5'-TTAC-3' motif. In addition, the sequences flanking the core motif are also involved in the protein-DNA interaction. The results demonstrate the importance of HD for direct binding to target sequences to regulate the expression level of the target genes.
Keywords: Abdominal-B, Castor, EMSA, Homeodomain, Homeotic gene

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