Hello, my name is Mark Parrish.  I joined the Krumlauf lab in January 2004 after receiving my Ph.D. in Neurobiology at the University of Pittsburgh under Paula Monaghan-Nichols studying the role of Spalt transcription factors in murine development.  Since joining the Krumlauf lab I have been involved in several projects investigating Hox gene function and regulation.  Hox genes are arranged in clusters and exhibit a “collinear” expression pattern both temporally and spatially.  Thus, expression of Hox genes occurs sequentially across the cluster from 3’ to 5’.  This translates into a pattern where 3’ Hox genes are generally expressed earlier during development and more rostrally while 5’ genes are expressed later and more caudally.  This complicated regulation appears to be the product of the influence of enhancer elements inside the complex and global/long-range influences outside the cluster.  A long-time goal of the lab has been to identify and characterize these influences.  I have been developing assay systems that will allow us to specifically examine long range influences.

              I am also interested in Hox gene function.  Hox genes play crucial roles in development by creating segmental identity, regulating migration and also cellular differentiation.  Very little is known about how these effects are mediated.  A second project that I am involved in will begin to analyze Hox gene function by taking biochemical approach.