title: Cloning, Sequencing, and the Expression of the Elusive Sarcomeric TPM4αIsoform in Humans.
abstract: In mammals, tropomyosin is encoded by four known TPM genes (TPM1, TPM2, TPM3, and TPM4) each of which can generate a number of TPM isoforms via alternative splicing and/or using alternate promoters. In humans, the sarcomeric isoform(s) of each of the TPM genes, except for the TPM4, have been known for a long time. Recently, on the basis of computational analyses of the human genome sequence, the predicted sequence of TPM4αhas been posted in GenBank. We designed primer-pairs for RT-PCR and showed the expression of the transcripts of TPM4αand a novel isoform TPM4δin human heart and skeletal muscle. qRT-PCR shows that the relative expression of TPM4αand TPM4δis higher in human cardiac muscle. Western blot analyses using CH1 monoclonal antibodies show the absence of the expression of TPM4δprotein (~28 kDa) in human heart muscle. 2D western blot analyses with the same antibody show the expression of at least nine distinct tropomyosin molecules with a mass ~32 kD and above in adult heart. By Mass spectrometry, we determined the amino acid sequences of the extracted proteins from these spots. Spot "G" reveals the putative expression of TPM4αalong with TPM1αprotein in human adult heart.
authors.affiliation: Department of Medicine, SUNY Upstate Medical University, 750 East Adams Street, Syracuse, NY 13210, USA.
authors.forename: Dipak K
authors.identifier: 0000-0002-0205-4761
authors.initials: DK
authors.lastname: Dube
authors.affiliation: Department of Medicine, SUNY Upstate Medical University, 750 East Adams Street, Syracuse, NY 13210, USA.
authors.forename: Syamalima
authors.identifier: 0000-0002-1179-7073
authors.initials: S
authors.lastname: Dube
authors.affiliation: Department of Medicine, SUNY Upstate Medical University, 750 East Adams Street, Syracuse, NY 13210, USA.
authors.forename: Lynn
authors.initials: L
authors.lastname: Abbott
authors.affiliation: Department of Medicine, SUNY Upstate Medical University, 750 East Adams Street, Syracuse, NY 13210, USA.
authors.forename: Ruham
authors.initials: R
authors.lastname: Alshiekh-Nasany
authors.affiliation: Department of Medicine, SUNY Upstate Medical University, 750 East Adams Street, Syracuse, NY 13210, USA.
authors.forename: Charles
authors.initials: C
authors.lastname: Mitschow
authors.affiliation: Department of Medicine, SUNY Upstate Medical University, 750 East Adams Street, Syracuse, NY 13210, USA.
authors.forename: Bernard J
authors.identifier: 0000-0002-1269-4658
authors.initials: BJ
authors.lastname: Poiesz