Christina M. Brakken-Thal


     Year Entered:   2006

     Degrees Received: 
     Williams College
     Mathematics major
     B.A., 2006

     Honors and Awards:
     -Member of Sigma Xi since June, 2006
     -Musculoskeletal Training Grant, 2012-2013

     Thesis Advisor: Hans Othmer, Ph.D., and Michael O'Connor,

     Research Interests: My research focuses on understanding
     how BMP signaling is controlled and helps specify the dorsal
     surface of Drosophila embryos.  Dpp, a BMP ligand, is produced uniformly over the dorsal surface, but over time Dpp signaling contracts and intensifies over the dorsal midline through a diffusion based transport mechanism in the perivitelline space.  Modeling studies have shown that for both the contraction and intensification to occur, a positive feedback mechanism must exist, but this has not been characterized to date.  The levels of Dpp are estimated to be between 10-100 molecules / nucleus, which would predict a significant level of noise in Dpp signaling.  However, this is not observed, so there must be mechanisms that dampen noise in signaling pathways.  I am using molecular biology, genetics, live cell imaging, and mathematical modeling techniques to identify possible mechanisms for positive feedback control of BMP signaling, to accurately quantify the levels and interactions of BMP protein and receptors in early development, and to elucidate mechanisms to dampen stochastic fluctuations in signaling molecules.  .