Exp Neurobiol 2003; 12(2): 111-116

Published online December 31, 2003

© The Korean Society for Brain and Neural Sciences

Molecular Cloning and Distribution Pattern of Human B/K mRNA

Oh-Joo Kwon1,*, Sung-Ho Choi2, Yoon-Seong Jang1, Seong-Whan Jeong1, In-Kyung Kim1 and Hemin Chin3

1Department of Biochemistry, College of Medicine, The Catholic University, of Korea, Seoul 137-701, Korea, 2R&D Center, PetaGen Inc., B199F Yonsei Engineering, Research Complex, Seoul 120-140, Korea, 3National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA

Correspondence to: *To whom correspondence should be addressed.
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The nucleotide sequence reported here is deposited in the GenBank under accession number AF220560.


We have previously isolated a novel protein with two C2-like domains from rat brain, and named it B/K based on its predominant expression in the brain and kidney. We now report isolation of a human brain cDNA encoding B/K protein, and its mRNA distribution in various human tissues. The 1.5 kb human B/K cDNA clone exhibits 89% and 97% identities with rat B/K in the sequences of nucleotide and amino acid, respectively. Human B/K isoform encoding a 474 amino-acid protein shows structural features that are in common with rat counterpart including two C2 domains in its C-terminal region, three consensus sequences for protein kinase A, the absence of transmembrane region, and conservation of N-terminal cysteine cluster. On northern and dot blot analyses, a human B/K cDNA probe hybridized to a 3.0 kb B/K transcript abundantly present in human brain, kidney, and prostate. Among the brain regions, strong signals were observed in the frontal and temporal lobes, hippocampus, hypothalamus, amygdala, substantia nigra, and pituitary. A high degree of conservation in the primary structure and the pattern of mRNA distribution between rat and human B/K suggest that B/K proteins play a specific role in the area where they are expressed.

Keywords: Protein kinase A, double C2 domain, calcium, cysteine cluster