Post-Doctoral Fellowships
Shaun Cowley, Ph.D.
Fred Hutchinson Cancer Research Center
Mentor: Robert N. Eisenman, Ph.D.
"Determining the role of the Co-repressor mSin3A in Mecp2 function"
2-Year Award: $100,000
Recipient of the Alan P. Wolffe Memorial Fellowship
Research Sponsor: Adam (Buddha) Lavey / Reading Rock, Inc.
Final Report (November 2005)
Mecp2, the gene most commonly mutated in Rett syndrome patients, is thought to function by inactivating other genes. It is aided in this role by the recruitment of a second gene product called mSin3A. Over the past two years with support from the RSRF I have been investigating the many roles of mSin3A.
The main job of mSin3A is to serve as a bridge between 'repressor' proteins which bind to DNA and help switch genes off, and enzymes called HDACs, which actually provide the silencing activity. In order to do this mSin3A has a number of docking sites known as 'PAH domains' that function as molecular 'Velcro'. Repressors, such as mecp2, are able to bind directly to mSin3A via these PAH domains and recruit it to DNA thus allowing the associated HDACs to switch genes off. As part of a collaborative team I was able to determine the first molecular structure, an actual picture, of a 'PAH domain' bound to a repressor. Using this detailed picture I was also able to distinguish which parts of the PAH domain are required to bind other proteins and how the specificity of such interactions are maintained. We are hopeful that this in-depth study will provide a useful example in trying to understand the many thousands of protein-protein interactions that occur within the cell nucleus.
In addition to this test-tube analysis of mSin3A function, we have also generated a mutant mouse lacking the mSin3A gene to better understand its biological role. Analysis of our mSin3A knock-out mouse model has demonstrated a requirement for mSin3A in the developing embryo and for the development of many other tissues including the cells of the immune system. A similar mutant mouse lacking the Mecp2 gene has been demonstrated to mimic many of the symptoms of patients with Rett syndrome, such as tremors and decreased physical ability. As part of an on-going study we are breeding heterozygous mSin3A mice (mice with only one functional copy of the gene) with Mecp2 knock-out animals and analyzing their off-spring. If mSin3A activity is important for Mecp2 function we might expect mice lacking both Mecp2 and one copy of mSin3A to have an increased severity of their neurological symptoms.
Shaun Cowley, Ph.D.Fred Hutchinson Cancer Research Center
Mentor: Robert N. Eisenman, Ph.D.
"Determining the role of the Co-repressor mSin3A in Mecp2 function"
2-Year Award: $100,000
Recipient of the Alan P. Wolffe Memorial Fellowship
Research Sponsor: Adam (Buddha) Lavey / Reading Rock, Inc.
Final Report (November 2005)
Mecp2, the gene most commonly mutated in Rett syndrome patients, is thought to function by inactivating other genes. It is aided in this role by the recruitment of a second gene product called mSin3A. Over the past two years with support from the RSRF I have been investigating the many roles of mSin3A.
The main job of mSin3A is to serve as a bridge between 'repressor' proteins which bind to DNA and help switch genes off, and enzymes called HDACs, which actually provide the silencing activity. In order to do this mSin3A has a number of docking sites known as 'PAH domains' that function as molecular 'Velcro'. Repressors, such as mecp2, are able to bind directly to mSin3A via these PAH domains and recruit it to DNA thus allowing the associated HDACs to switch genes off. As part of a collaborative team I was able to determine the first molecular structure, an actual picture, of a 'PAH domain' bound to a repressor. Using this detailed picture I was also able to distinguish which parts of the PAH domain are required to bind other proteins and how the specificity of such interactions are maintained. We are hopeful that this in-depth study will provide a useful example in trying to understand the many thousands of protein-protein interactions that occur within the cell nucleus.
In addition to this test-tube analysis of mSin3A function, we have also generated a mutant mouse lacking the mSin3A gene to better understand its biological role. Analysis of our mSin3A knock-out mouse model has demonstrated a requirement for mSin3A in the developing embryo and for the development of many other tissues including the cells of the immune system. A similar mutant mouse lacking the Mecp2 gene has been demonstrated to mimic many of the symptoms of patients with Rett syndrome, such as tremors and decreased physical ability. As part of an on-going study we are breeding heterozygous mSin3A mice (mice with only one functional copy of the gene) with Mecp2 knock-out animals and analyzing their off-spring. If mSin3A activity is important for Mecp2 function we might expect mice lacking both Mecp2 and one copy of mSin3A to have an increased severity of their neurological symptoms.