Alternative titles; symbols
HGNC Approved Gene Symbol: MAMSTR
Cytogenetic location: 19q13.33 Genomic coordinates (GRCh38): 19:48,705,718-48,719,725 (from NCBI)
By searching mouse and human databases for sequences similar to the MEF2 (see MEF2C; 600662)-interacting domain of myocardin (MYOCD; 606127), followed by PCR of a mouse skeletal muscle cDNA library, Creemers et al. (2006) cloned mouse Mastr. The deduced 421-amino acid mouse protein has an N-terminal MEF2-binding domain and a central proline-rich region containing a SAP domain. Northern blot analysis of human tissues detected a 1.8-kb MASTR transcript in skeletal muscle, brain, placenta, and spleen. Real-time PCR of mouse tissues detected highest Mastr expression in skeletal muscle, lung, aorta, brain, and heart. In transfected COS cells, Mastr localized exclusively in the nucleus.
Using a reporter gene assay, Creemers et al. (2006) found that mouse Mastr had no transcriptional activity alone, but it stimulated transcriptional activity of Mef2c. Deletion and pull-down experiments showed that the N-terminal domain of Mastr was required for Mastr to associate with and activate Mef2c. Deletion of the SAP domain augmented Mastr transcriptional activity. Mutation analysis localized the transcriptional activation domain to the C-terminal half of Mastr, and deletion of this region completely abolished the ability of Mastr to stimulate Mef2-dependent transcription. Expression of Mastr in mouse fibroblasts enhanced the promyogenic activity of MyoD (MYOD1; 159970).
Hartz (2008) mapped the MAMSTR gene to chromosome 19q13.33 based on an alignment of the MAMSTR sequence (GenBank AK131427) with the genomic sequence (build 36.1).
Using dominant-negative constructs or morpholino knockdown, Meadows et al. (2008) showed that reduced Mastr expression in Xenopus embryos led to a dramatic reduction in expression of skeletal muscle marker genes. Overexpression of Mastr in whole embryos or embryonic tissue explants induced ectopic expression of muscle marker genes. Mastr cooperated with MyoD and Myf5 (159990) to activate transcription of skeletal muscle genes.
Creemers, E. E., Sutherland, L. B., Oh, J., Barbosa, A. C., Olson, E. N. Coactivation of MEF2 by the SAP domain proteins myocardin and MASTR. Molec. Cell 23: 83-96, 2006. [PubMed: 16818234] [Full Text: https://doi.org/10.1016/j.molcel.2006.05.026]
Hartz, P. A. Personal Communication. Baltimore, Md. 4/15/2008.
Meadows, S. M., Warkman, A. S., Salanga, M. C., Small, E. M., Krieg, P. A. The myocardin-related transcription factor, MASTR, cooperates with MyoD to activate skeletal muscle gene expression. Proc. Nat. Acad. Sci. 105: 1545-1550, 2008. [PubMed: 18230740] [Full Text: https://doi.org/10.1073/pnas.0703918105]