Analysis of sense and naturally occurring antisense transcripts of myosin heavy chain in the human myocardium

Naturally occurring antisense RNA has the potential to form a duplex with its complementary sense mRNA, thereby regulating protein expression. Previously, we demonstrated considerable amounts of endogenous antisense RNA for both α‐ and β‐myosin heavy chain (MHC) in rat heart suggesting a role in posttranscriptional MHC‐regulation (Luther et al. [1997] J Mol Cell Cardiol 29(1):27–35). To evaluate whether antisense RNA is also involved in MHC regulation in human heart we analyzed ventricular myocardium transcripts in nonfailing hearts (n=3) and hearts from patients undergoing heart transplantation (n=5). Investigation of RNA by reverse transcription polymerase chain reaction (RT‐PCR) detected an antisense RNA transcript for β‐MHC but none for α‐MHC. Northern blot analysis of normal and failing hearts detected sense mRNA for β‐MHC, but not α‐MHC suggesting no functionally relevant levels of α‐MHC mRNA exist in the human ventricle. The results describe—for the first time—the existence of endogenous polyadenylated MHC antisense transcripts in the human heart. The potential effect of attenuating translation was shown in an in vitro translation assay using a synthetic antisense‐oligonucleotide derived from the sequence of the naturally occurring antisense RNA. J. Cell. Biochem. 80:596–605, 2001. © 2001 Wiley‐Liss, Inc.