(A) Structure of mouse cardiac MyBP-C protein (cMyBP-C). The numbers above
cMyBP-C indicate the position of each IgI domain (open square) and FN type III
repeat (circle). The cardiac-specific phosphorylation domain is shown as a
shaded square (P). Position of 10 amino acids insertion is indicated in C9
domain. (B) Genomic sequence and deduced amino acid sequence encoding the C9
IgI domain of mouse cardiac MyBP-C. The nucleotide sequence of the coding
region and the deduced amino acid sequence of MyBP-C(+) are represented in
capital letters. Exon 30 and 31B are highlighted by hatch. MyBP-C(+)-specific
insert sequence (exon 31A) is indicated by a box. Arrows indicate the location
of primer F (#F), primer I (#I) and primer R (#R). Asterisks indicate a
5′ splice donor sequence, gt, and 3′ splice acceptor sequence,
CAG. (C) Identification of MyBP-C(+) in C57BL/6J and ICR mice. cDNA libraries
prepared from 8-wk-old C57BL/6J hearts (lane 1 and 2) or from ICR hearts (lane
3 and 4) were subjected to PCR by using a primer F + R set (lane 1 and 3) or
using a primer F + I set (lane 2 and 4). Primer F + R set amplifies 212-base
pair and 182-base pair DNA fragments which are generated from MyBP-C(+) and
MyBP-C(–) cDNA, respectively. Primer F + I set specifically detects
MyBP-C(+) cDNA as a 118-base pairs product. A molecular weight marker (MW)
indicates 400, 300, 200, and 100 base pairs, top to bottom. (D) Schematic
genomic structure of mouse cardiac MyBP-C. Both MyBP-C(–) and MyBP-C(+)
mRNAs are encoded by a single gene and generated by an alternative mRNA
splicing.