Erik Griffin

All animals begin life as a single cell, the newly fertilized egg. As embryos develop, they generate the diverse array of cell types that make up the adult organism. We are interested in understanding how embryos generate diverse cell types, with a focus on the process of asymmetric cell division. When a cell divides asymmetrically, it generates two daughter cells with different functions, fates or sizes. For example, stem cells often divide asymmetrically to generate a stem cell and a cell that differentiates. We use the embryo of the nematode worm C. elegans to study the mechanisms of asymmetric cell division. Shortly after fertilization, the one-cell cell C. elegans embryo divides asymmetrically to give rise to a somatic and a germline daughter cell. This process is controlled by a conserved group of cell polarity regulators called the PAR proteins. The PAR proteins orchestrate the partitioning of cytoplasmic RNA-binding proteins to either the somatic or germline daughter cell. These RNA-binding proteins establish the distinct translation programs that give these cells their unique identities. We are interested in two key questions. First, how do the PAR proteins, which concentrate the cell cortex/plasma membrane control the segregation of RNA-binding proteins deep in the cytoplasm? Second, how do these RNA-binding proteins function to either activate or repress the translation of target mRNAs? We approach these questions by combining quantitative live imaging with genetic and biochemical approaches.