Tatjana Piotrowski
Investigator, Stowers Institute for Medical Research
In our laboratory we are studying the molecular mechanisms underlying morphogenesis and collective cell migration, as well as sensory hair cell regeneration.
Cell migration is a fundamental, tightly coordinated process during development and in adult animals. The mechanisms integrating migration and morphogenesis of groups of cells in vivo are among the least understood processes in developmental biology. During development, groups of cells self-organize into three-dimensional morphologies that are crucial for the function of tissues, organs and organisms (Aman and Piotrowski, 2010). Although it is widely appreciated that morphogenesis emerges from the coordinated behavior of many cells, understanding morphogenesis in terms of the molecular regulation of basic cell behaviors such as proliferation, cell migration and cell shape changes has proven to be a formidable challenge. Important questions awaiting satisfactory mechanistic explanations include how cluster polarity is maintained and how tip cells communicate with cells in the back to ensure coordinated, directed migration.
Over the past few years my lab has made important contributions to develop the zebrafish posterior lateral line system into a powerful system with which to interrogate the complex cell-cell signaling interactions and cell behaviors that occur in vertebrate morphogenesis. This is due to the relatively simple morphology and accessibility of the lateral line and the amenability of the zebrafish model to detailed genetic experimentation. The cell behaviors that drive morphogenesis can be observed directly in the living embryo and correlated with specific molecular perturbations afforded by the wealth of tools available for zebrafish research
Pablo Jenik
Associate Professor of Biology, Franklin & Marshall College
I am interested in understanding how plant embryos are made. I am particularly interested in the processes of patterning (how different cell types are specified in the right places) and maturation (the accumulation of products necessary to germinate succesfully). The embryo of the mustard weed Arabidopsis thaliana is an excellent model system to address these issues, since its development is characterized by extremely regular cell divisions and patterning decisions, which make it easy to find mutants that affect these events.
In my first years as faculty, my lab characterized several mutants with altered embryonic patterning. The work involved a careful study of the mutant phenotypes, a search for the genes that had been mutated and then, using genetic and molecular approaches, an analysis of how the products of those genes regulated development. We worked on genes that encode products involved in the synthesis of microRNAs (DICER-LIKE1) or that regulated protein degradation (proteasome subunit RPN5a, subunits of the CSN complex).
In the last few years we have switched our focus to the latter part of embryogenesis. We are are now studying the mechanisms than control the onset of the maturation program, both at the genetic and physiological levels, mostly using Arabidopsis, but considering to expand to other related species.