An evolutionarily conserved Myostatin proximal promoter/enhancer confers basal levels of transcription and spatial specificity in vivo

Abstract

Myostatin (Mstn) is a negative regulator of skeletal muscle mass, and Mstn mutations are responsible for the double muscling phenotype observed in many animal species. Moreover, Mstn is a positive regulator of adult muscle stem cell (satellite cell) quiescence, and hence, Mstn is being targeted in therapeutic approaches to muscle diseases. In order to better understand the mechanisms underlying Mstn regulation, we searched for the gene's proximal enhancer and promoter elements, using an evolutionary approach. We identified a 260-bp-long, evolutionary conserved region upstream of tetrapod Mstn and teleost mstn b genes. This region contains binding sites for TATA binding protein, Meis1, NF-Y, and for CREB family members, suggesting the involvement of cAMP in Myostatin regulation. The conserved fragment was able to drive reporter gene expression in C2C12 cells in vitro and in chicken somites in vivo; both normally express Mstn. In contrast, the reporter construct remained silent in the avian neural tube that normally does not express Mstn. This suggests that the identified element serves as a minimal promoter, harboring some spatial specificity. Finally, using bioinformatic approaches, we identified additional genes in the human genome associated with sequences similar to the Mstn proximal promoter/enhancer. Among them are genes important for myogenesis. This suggests that Mstn and these genes may form a synexpression group, regulated by a common signaling pathway.

Myostatin-induced inhibition of the long noncoding RNA Malat1 is associated with decreased myogenesis

“…Although Malat1 is known to be capable of regulating tumor development and metastasis, this is the first time it has been characterized in skeletal muscle, let alone implicated in skeletal myogenesis. Althought the mechanisms by which myostatin regulates the expression of Malat1 and by which Malat1 regulates Cdk6 and myogenin expression still need to be elucidated, both Malat1 and myostatin contain a cAMP-response elements in their proximal promoter as do many myogenic genes (7,17). This suggests that myostatin and Malat1 may be regulated by a common signaling pathway.…”

MEF2 Transcription Factors Regulate Distinct Gene Programs in Mammalian Skeletal Muscle Differentiation

“…Meis1 and Pknox2 are members of a small family of transcription factors that function in skeletal muscle as pioneer transcription factors to stabilize the MyoD/E12 DNA interaction on suboptimal E box sites, such as the E box found on the myogenin promoter (32)(33)(34). Although little is known about the function of Pknox2, it is similar in homology to Meis1 and is highly expressed in skeletal muscle tissue (35).…”

Characterization of 5′ Upstream Region and Investigation of TTTTA Deletion in 5′ UTR of Myostatin (MSTN) Gene in Indian Goat Breeds

“…However, few studies have reported on the characterization of the promoter which exhibits more divergence across the species (5)(6)(7). The level of conservation of several regulatory motifs in MSTN promoter among different species is not known to a greater extent (8).…”