Characterization of naturally occurring myosin heavy chain antisense mRNA in rat heart

Luther, Hans‐Peter; Haase, Hannelore; Hohaus, Annette; Beckmann, Georg; Reich, Jens; Morano, Ingo

doi:10.1002/(sici)1097-4644(19980701)70:1<110::aid-jcb11>3.3.co;2-k

Cited by 7 publications

(8 citation statements)

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“…Furthermore, this report of the antisense expression has not linked its expression with a functional significance. More recently, Luther et al (33)(34)(35) reported the expression of antisense MHC mRNA in both the rat and human myocardium, and it was proposed that this antisense MHC regulates translation of the sense mRNA into protein. In these studies (33)(34)(35), there was no differentiation between primary transcript versus processed mature mRNA.…”

Section: Discussionmentioning

confidence: 99%

Role of Antisense RNA in Coordinating Cardiac Myosin Heavy Chain Gene Switching

Haddad

Bodell

Qin

et al. 2003

Journal of Biological Chemistry

102

101

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A novel mechanism of regulation of cardiac ␣ and ␤ myosin heavy chain gene by naturally occurring antisense transcription was elucidated via pre-mRNA analysis. Herein, we report the expression of an antisense ␤ myosin heavy chain RNA in the normal rodent myocardium. The pattern of expression of the antisense ␤MHC RNA (␤ RNA) under altered thyroid state and in diabetes directly correlates with that of the ␣ pre-mRNA/mRNA, whereas it negatively correlates with the ␤ mRNA expression. Rapid amplification of the 5 end shows that this antisense transcript originates 2 kb downstream of the ␤ gene, and it is transcribed across the entire ␤ gene from the opposite strand. Our results demonstrate that the ␤-␣ myosin heavy chain intergenic DNA possesses a bidirectional transcriptional activity, one direction transcribing the ␣ gene, and the opposite direction transcribing the antisense ␤ RNA. This process turns on the ␣ expression, and it simultaneously turns off that of the ␤ and thus coordinates ␣ and ␤ expression in an opposite fashion. Comparative analyses of the intergenic DNA sequence across five mammalian species revealed a conserved region that is proposed to be a common regulatory region for the ␣ and antisense ␤ promoter. This finding unravels the mechanism of cardiac ␣-␤ gene switching and implicates the role of cardiac myosin gene organization with their function.Cardiac muscle expresses two myosin heavy chain (MHC) 1 isoforms designated as ␣ (high ATPase) and ␤ (low ATPase) that are encoded by two distinct genes located in close proximity on the same chromosome (1-4). The MHC is the molecular motor driving muscle contraction, and its phenotypic composition regulates the intrinsic contraction properties of the heart (5, 6). Cardiac MHC isoform expression is developmentally regulated (5), and it can change totally in either direction under certain pathophysiological states (7-9). For example during the first 3 weeks of postnatal life of rodents there is a complete switch from a predominant ␤MHC expression at birth (Ͼ90%) to a predominant ␣MHC expression at 3 weeks of age (Ͼ95%). Throughout adult life, the ␣MHC expression predominates in a normal rodent heart, with ␤MHC expression gradually increasing as the animal gets older. At any time during life, the pattern of MHC expression can be altered. Hypothyroidism and diabetes are associated with a switch in the cardiac MHC gene expression from a predominant ␣MHC to a predominant ␤MHC. In contrast, thyroid hormones treatment increases the ␣MHC expression while down-regulating the ␤MHC expression. The exact molecular mechanisms causing this tightly coordinated regulation of these two genes remains unclear. Thyroid hormone has been shown to be a major regulator of MHC gene expression, and its regulation is thought to occur mainly via transcriptional processes regulating each gene independently in a well coordinated fashion (8). Several thyroid responsive elements have been located on the promoter of the ␣MHC gene, whereas the localized action of thyroid hormone on the ...

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Section: Discussionmentioning

confidence: 99%

Role of Antisense RNA in Coordinating Cardiac Myosin Heavy Chain Gene Switching

Haddad

Bodell

Qin

et al. 2003

Journal of Biological Chemistry

102

101

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“…Our group is focusing on natural antisense RNAs from cardiac tissues and we were previously able to isolate different antisense RNAs, including ␣ and ␤ myosin heavy chain (MyHC; Luther et al 1998) and cardiac troponin I (cTnI) antisense RNAs (Podlowski et al 2002). Our investigations with cTnI antisense RNA have so far revealed cTnI antisense-sense duplex structures in vivo and reduced protein expression with oligonucleotides directed against the sense RNA in vitro (Podlowski et al 2002).…”

Section: Introductionmentioning

confidence: 99%

Detection of a novel sense–antisense RNA-hybrid structure by RACE experiments on endogenous troponin I antisense RNA

Bartsch

Voigtsberger²,

Baumann³

et al. 2004

RNA

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Conformational changes in the troponin/tropomyosin complex significantly alter the mechanical properties of cardiac muscle. Phosphorylation of cardiac troponin I, part of the troponin/tropomyosin complex, reduces calcium affinity, which leads to increased relaxation of cardiac muscle. Because cardiac troponin I plays a central role in tuning the heart to different work demands, detailed knowledge of troponin I protein regulation is required. Our group previously detected naturally occurring antisense RNA for troponin I in human and rat hearts, and here, attempt to unravel the structure of rat cardiac troponin I antisense RNA. We performed rapid amplification of cDNA ends (RACE) experiments and discovered antisense sequences identical to a copy of the sense mRNA, which led us to conclude that the antisense RNA must be transcribed from troponin I mRNA in the cytoplasm. Moreover, we isolated RNA structures comprising sense and antisense sequences in one continuous molecule. As we found no homolog structures described in the literature, we called this "hybrid RNA." Because a duplex formation was demonstrated previously we concluded that hybrid RNA is a consequence of a tight interaction between sense and antisense troponin I RNA in vivo, which we discuss in the article.

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“…However, RT was performed using the specific forward primers. We were unable to detect any ␣-MHC antisense RNA in hypothyroid or euthyroid rat hearts (12,22). However, ␤-MHC antisense RNA was present in euthyroid, and at substantially lower levels in hypothyroid, rat hearts.…”

Section: Resultsmentioning

confidence: 59%

“…To identify a mechanism for the stabilization of ␣-MHC mRNA after treatment with actinomycin D, we hypothesized that the absence of a short-lived ␣-MHC antisense RNA may account for the increased stability of ␣-MHC mRNA. To validate the RT-PCR method for antisense RNA, we found it necessary to ensure the adequacy of the denaturation of the reverse transcriptase as described in MATERIALS AND METHODS (12,22). Our findings, however, did not support this hypothesis, because we could detect no antisense ␣-MHC in ventricular myocytes.…”

Section: Discussionmentioning

confidence: 73%

Posttranscriptional regulation of myosin heavy chain expression in the heart by triiodothyronine

Danzi

Klein²

2005

American Journal of Physiology-Heart and Circulatory Physiology

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Danzi, Sara, and Irwin Klein. Posttranscriptional regulation of myosin heavy chain expression in the heart by triiodothyronine. Am J Physiol Heart Circ Physiol 288: H455-H460, 2005; doi:10.1152 doi:10. / ajpheart.00896.2004 regulates cardiac contractility in part by regulating the expression of several important cardiac myocyte genes. In the rat, the T3-mediated induction of ␣-myosin heavy chain (MHC) transcription in hypothyroid hearts is rapid, exhibiting zero-order kinetics, whereas the repression of ␤-MHC in these same hearts is much slower. To elucidate the mechanism for T3 transcriptional as well as posttranscriptional regulation of both MHC gene isoforms, we used an RT-PCR-based transcription assay and the RNA polymerase II inhibitor actinomycin D in an in vivo model to simultaneously measure specific ␣-and ␤-MHC heterogeneous nuclear RNA (hnRNA), mRNA kinetics, and MHC antisense RNA. In vivo actinomycin D treatment blocked ␣-MHC transcription in euthyroid rats by Ͼ80% at 2 h and suggested a half-life of ␣-MHC hnRNA of ϳ1 h, whereas actinomycin D inhibited ␤-MHC transcription in hypothyroid rats by Ͼ75% at 6 h, suggesting a significantly longer hnRNA half-life of ϳ4 h. The effect of actinomycin D on ␤-MHC transcription was independent of T3. T3 treatment in hypothyroid animals caused ␤-MHC mRNA to decline more rapidly than ␤-MHC hnRNA, demonstrating, for the first time, a posttranscriptional mechanism(s). The measured change in ␤-MHC mRNA half-life indicates a T3-mediated destabilization of ␤-MHC mRNA. To understand the mechanism by which T3 destabilizes ␤-MHC mRNA, we measured ␤-MHC antisense RNA. ␤-MHC antisense RNA is present in euthyroid myocytes, but levels are not significant in hypothyroid myocytes. This differential expression may explain some of the effects of T3 on MHC posttranscriptional regulation. thyroid hormone; myocardium; gene transcription; actinomycin D; RNA stability; heterogeneous nuclear RNA THYROID HORMONE is an important regulator of cardiac contractile function (9, 18). Triiodothyronine (T 3 ), the physiologically active form of thyroid hormone, regulates the expression of several important cardiac genes, which include the myosin heavy chain (MHC) gene isoforms ␣-and ␤- MHC (4,8,23,25). In euthyroid rats, ␣-MHC is maximally expressed and ␤-MHC is repressed. In thyroidectomized rats, the opposite occurs (8,9,23,25). Our understanding of the regulation of the MHC genes is primarily derived from the T 3 -mediated positively regulated ␣-MHC, whereas less is understood regarding the negative regulation of the ␤-MHC gene (2,3,10,25,34,41). ␤-MHC is the predominant myofibrillar protein in the human heart, and it has been shown by others that, in the failing human heart, ␣-MHC mRNA is decreased and ␤-MHC mRNA is increased, possibly contributing to decreased contractility in the failing heart (21, 26, 31).T 3 mediates the transcription of ␣-MHC as follows: T 3 binds to nuclear receptor proteins (TRs), which in turn bind to TR response elements (TREs) in the promoter regions of positively ...

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Characterization of naturally occurring myosin heavy chain antisense mRNA in rat heart

Cited by 7 publications

References 0 publications

Role of Antisense RNA in Coordinating Cardiac Myosin Heavy Chain Gene Switching

Role of Antisense RNA in Coordinating Cardiac Myosin Heavy Chain Gene Switching

Detection of a novel sense–antisense RNA-hybrid structure by RACE experiments on endogenous troponin I antisense RNA

Posttranscriptional regulation of myosin heavy chain expression in the heart by triiodothyronine

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