Complete sequence of human cardiac α‐myosin heavy chain gene and amino acid comparison to other myosins based on structural and functional differences

Abstract

We have obtained the 5820 nucleotide sequence encoding all 1939 amino acids of the human cardiac alpha-myosin heavy chain (alpha-MHC), as established by dideoxy sequencing of cloned cDNA, genomic DNA and polymerase chain reaction (PCR) amplification products. This sequence represents overlapping fragments of the entire coding sequence. Amino acid sequence comparison of the human cardiac alpha-MHC with the published human cardiac beta-MHC have demonstrated that there are, at least, 7 isoform-specific divergent regions, including functionally important binding protein-related sites such as ATP, actin and myosin light chain. It has been reported that in the rat, there are 8 isoform-specific divergent regions. The 7th divergent area (residue area 1633-1657, which is thought to mediate thick filament formation) in the light meromyosin region in the rat is not apparent in the human. The amino acid compositions of cardiac alpha- and beta-MHCs in the human and the rat, and human embryonic skeletal muscle and chicken gizzard smooth muscles were compared. Amino acid sequences in cardiac alpha- and beta-MHCs in the human and the rat are well conserved. In the head portion, the amino acid composition divergence of human cardiac alpha-MHC is ranked between rat cardiac alpha-MHC and human cardiac beta- or rat cardiac beta-MHC; human skeletal muscle MHC is the most divergent of the myosin isoform examined. These data predict that human cardiac alpha-MHC may have undergone evolutionary changes toward obtaining the biochemical and physiological properties of cardiac beta-MHC.

Myosin heavy chain gene expression in human heart failure.

“…To ensure the identity of the product, direct sequencing of the 217-bp cDNA was performed for two specimens, DHD-1 and F-1 (Tables I and II). The obtained sequences demonstrated that the fragment from F-1 was ␤-MyHC, whereas the amplified DHD-1 fragment after digestion with PstI corresponded to ␣-MyHC cDNA (data not shown) (17,19). The amplified region spanned two splice junctions (Fig.…”

“…Two oligonucleotides (5 Ј primer, 5 Ј -AGCAGAAGCGCA-ACGCAGAGT-3 Ј ; and 3 Ј primer, 5 Ј -TGCTGCACCTTGCGGAAC-TTG-3 Ј ) were designed from reported ␣ -and ␤ -MyHC cDNA sequences (17,19), and synthesized by GIBCO BRL. These primers are identical in sequence in ␣ -and ␤ -MyHC, and the amplified 217-bp sequence was 96% identical in ␣ -and ␤ -MyHC (Fig.…”

“…The 5 Ј primers are located in exons 36 and 37 of ␣ -and ␤ -MyHC genes, respectively, while the 3 Ј primers are in exons 38 and 39, respectively. The amplified regions correspond to nucleotides 5492-5708 and 5572-5788 in ␣ - (17) and ␤ -MyHC cDNA (19), respectively. The two exon/intron boundaries are conserved (17)(18)(19)(20).…”

“…Immunohistochemistry allows the spatial expression of each isoform to be determined, but is not quantitative, and two different antibodies cannot be compared directly (15,16). Since human ␣ -and ␤ -MyHCs are 93% homologous, it is not surprising that the discrimination of cardiac MyHC isoforms is difficult at the protein level (17)(18)(19)(20). The results of immunohistochemical analysis were quite varied with reports ranging from Ͻ 5 up to 88% of myocytes expressing ␣ -MyHC (8,11,12).…”

PRIMARY PEPTIDE SEQUENCES FROM SQUID MUSCLE AND OPTIC LOBE MYOSIN IIs: A STRATEGY TO IDENTIFY AN ORGANELLE MYOSIN

“…Bovine myosin I sequence (P10568): Hoshimaru et al, 1987; C. elegans muscle myosin II sequence (P02567): Dibb et al, 1989; chicken myosin V sequence (S19188): Espreafico et al, 1992; chicken nonmuscle myosin IIA sequence (P14105): Shohet et al, 1989; chicken smooth muscle myosin II sequence (P10587): Yanagisawa et al, 1987; fruit fly myosin VI sequence (Q01989): Kellerman et al, 1992; fruit fly nonmuscle myosin IIB sequence (A36014): Ketchum et al, 1990; human cardiac muscle myosin II sequence (P13533): Matsuoka et al, 1991; pig myosin VI sequence (A54818): Hasson and Mooseker, 1994; rabbit smooth muscle myosin II sequence (P35748): Babij et al, 1991; rat cardiac muscle myosin II sequence (P02564): Kraft et al, 1989; rat skeletal muscle myosin II sequence (P12847): Strehler et al, 1986; scallop myosin II sequence (P24733): Nyitray et al, 1991. …”