Jennifer Zallen heads a laboratory in the Developmental Biology Program at Sloan-Kettering Institute and is a Howard Hughes Medical Institute Early Career Scientist. Her lab investigates how large-scale changes in tissue organization arise from processes that occur on a cellular and molecular level. Her lab uses a combination of genetics and molecular biology, quantitative cell imaging, and computational and biophysical approaches to understand how genes encode the forces that generate three-dimensional structure during development.
The processing from pre-miRNA to mature miRNA in plants involves a mechanism, which depends on an extended stem in the secondary structure of the pre-miRNA. Here, we show how natural selection acts on this secondary structure to produce evolutionary conservation of the processing mechanism together with modularity of the pre-miRNA molecules, making this molecular function independent of others. Our main results are: 1. Selection on miRNA processing can be described by a fitness landscape which depends directly on the secondary structure of the pre-miRNA. 2.
The focus of our research is to develop ways of tracking ions, molecules, and proteins in cells using fluorescence microscopy. We have created genetically encoded sensors that utilize FRET to track calcium and zinc ions in cells. We utilize these sensors to study metal homeostasis and define dynamics during signaling processes. We have also developed ways of imaging bacterial protein secretion so we can monitor pathogenic proteins in host cells. Using this methodology we have identified bacterial proteins that interact with and perturb vesicle trafficking in host cells.
A team led by Thomas Gregor, an assistant professor of physics and the Lewis-Sigler Institute for Integrative Genomics at Princeton University, and Shawn Little, a visiting postdoctoral research associate in the laboratory of Professor Eric Wieschaus in the Department of Molecular Biology at Princeton, has published in the March 1 issue of the journal PLoS Biology results of research into the fruit fly Drosophila that introduces
Hydra is an about cm sized polyp of roughly 10^5 cells exhibiting surprising robustness: it can regenerate even from a random cell aggregate made from its own cells. During such a reorganization, hydra first forms a hollow cell sphere. We show that even a weak temperature gradient directs the axis of the regenerating animal — but only if it is applied during the symmetry-breaking moment. We observe that the spatial distribution across the cell sphere of the early expressed, head-specific gene ks1 has become scale-free and fractal at that point.
Our laboratory studies how micro- and nanoscale systems can be deployed to understand, diagnose, and treat human disease. In this talk, I will describe our progress in two application areas: liver disease and cancer. In the area of hepatic tissue engineering, we are developing microtechnology tools to understand how ensembles of cells coordinate to produce tissues with emergent properties in the body.
Ultrasensitive, threshold responses are critical for robust bistability (e.g. epigenetic switches) and oscillation (e.g. clocks, cell cycle) in regulatory networks. Protein sequestration, where an active protein is bound in an inactive complex by an inhibitor, is a common molecular mechanism in natural regulatory circuits.
Kellen Olszewski, a graduate student in Manuel Llinás' group has been selected to receive a 2011 Harold M. Weintraub Graduate Student Award sponsored by the Basic Sciences Division of the Fred Hutchinson Cancer Research Center. Kellen is one of twelve graduate students to be chosen for this award. Nominations were solicited internationally; the winners were selected on the basis of the quality, originality and significance of their work.