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University of Colorado Denver College of Liberal Arts and Sciences

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Faculty & Staff Directory

Aaron Johnson, Ph.D.

Dr. Aaron Johnson

​Associate Professor


Office Location: SI 4099

Phone: (303) 556-2593

Fax: (303) 556-4352

2014 Fall Office Hours:  
W 9:00a-10:00a, THU 9:30a-10:30a

Areas of Expertise: Genetics, Embryonic Development, Molecular Biology


Ph.D., Biology (Genetics), Arizona State University

Postdoctoral Training, UT Southwestern Medical Center at Dallas, Eric Olson Laboratory


Our lab studies the molecular mechanisms that direct muscle development.  Muscle cells are highly specialized and their formation requires the coordinated expression of arrays of genes involved in contractility.  These unique properties make muscle cells an excellent model for understanding broad developmental concepts including cell fate specification and mechanisms of differentiation.  The molecular pathways that control muscle development evolved early in the Metazoan lineage and are highly conserved among diverse species.  This conservation allows us to use high throughput genetic screens in fruit flies to discover novel proteins that direct cardiac and somatic (skeletal) muscle development; most of these proteins have vertebrate counterparts with similar functions.  Our specific interests are two fold.  First, we are interested in understanding how transcription factors and extracellular signals regulate cardiac development.  More recently, we discovered a novel RNA regulatory pathway that coordinates skeletal muscle development.  Sarcomeres are the basic contractile unit of muscle and we have identified a conserved master regulator of RNAs that encode sarcomeric proteins during embryonic muscle development.  This example supports a fairly novel concept that RNAs encoding structurally similar proteins are post-transcriptionally co-regulated by a common set of RNA binding proteins.  RNA co-regulation appears to be a broad developmental strategy that accurately and efficiently generates macromolecular structures in differentiating cells.  We are working to define the architecture of the RNA regulatory circuits during development. 

Refereed Publications

Mokalled, M.H., A.N. Johnson, E. Creemers, S. Qi, and E.N. Olson (2012). MASTR coactivates MEF2 and cooperates with MRTF-A to direct MyoD-dependent satellite cell differentiation during skeletal muscle regeneration.  Genes and Development 26, 190-202.
Johnson, A.N., M.H. Mokalled, T.N. Haden, and E.N Olson (2011). JAK/Stat signaling regulates heart precursor diversification in Drosophila. Development 138: 4627-38
Mokalled, M.H., A.N. Johnson, Y. Kim, J. Oh, and E.N Olson (2010). Myocardin-related transcription factors regulate the Cdk5/Pctaire1 kinase cascade to control neurite outgrowth, neuronal migration and brain development. Development 137:2365-74
Haberland, M., A.N. Johnson, M.H. Mokalled, R.L. Montgomery, and E.N. Olson (2009).  Genetic dissection of histone deacetylase requirement in tumor cells. PNAS 106: 7751-5.
*Yi P, A.N., Johnson*, Z. Han, J. Wu, and E.N. Olson (2008). Heterotrimeric G proteins regulate a noncanonical function of septate junction proteins to maintain cardiac integrity in Drosophila. Developmental Cell 15 704-13. (*co-first authors)
Takaesu, N.T., D.S. Bulanin, A.N. Johnson, T.V. Orenic, and S.J. Newfeld (2008). A combinatorial enhancer recognized by Mad, TCF and Brinker first activates then represses dpp expression in the posterior spiracles of Drosophila.  Developmental Biology. 313(2):829-43.
Johnson, A.N., L.A. Burnette,  J. Sellin, A. Paululat, and S.J. Newfeld (2007). Defective Dpp signaling results in heart overgrowth and reduced cardiac output in Drosophila. Genetics 176: 1609-24.
Johnson, A.N., C.M. Bergman, M. Kreitman, and S.J. Newfeld (2003).  Embryonic enhancers in the dpp disk region regulate a second round of Dpp signaling from the dorsal ectoderm to the mesoderm that represses Zfh-1 expression in a subset of pericardial cells.  Developmental Biology 262: 137-151.
Wisotzkey, R.G., A.N. Johnson, N.T. Takaesu, and S.J. Newfeld (2003).  a/b-hydrolase2, a predicted gene adjacent to Mad in Drosophila melanogaster, belongs to a new global multigene family and is associated with obesity.  Journal of Molecular Evolution 56: 351-361.
Johnson, A.N. and S.J. Newfeld (2002).  The TGF-b family: Signaling pathways, developmental roles, and tumor suppressor activities.  TheScientificWorldJournal 2:892-925.(invited review)
Takaesu, N. T., A. N. Johnson, O.H. Sultani, and S.J. Newfeld (2002). Posterior spiracle specific GAL4 lines: new reagents for developmental biology and respiratory physiology. Genesis 34: 16-8.
Takaesu, N. T., A. N. Johnson, and S.J. Newfeld (2002). Combinatorial signaling by an unconventional Wg pathway and the Dpp pathway requires Nejire (CBP/p300) to regulate dpp expression in posterior tracheal branches. Developmental Biology 247: 225-36.