Maxwell G. Heiman, Ph.D.
Assistant Professor of Genetics
Center for Life Science, Room 14-047
3 Blackfan Circle
Boston, MA 02115
My brain does not look like yours – the arrangement and connectivity of our nerve cells differ due to stochastic developmental noise and experience-dependent plasticity. However, layered under these differences are fundamental similarities that we share, and that are shared among most human brains throughout history. What are the basic rules of neuronal shape and connectivity, and how are they encoded in our genes?
To get at this question, we study the nervous system of the nematode C. elegans, which we chose for two remarkable properties. First, it contains a small, defined set of neurons – exactly 302 in the adult hermaphrodite – which always arise by the same series of cell divisions. Second, the shapes and wiring of these neurons are nearly identical in every individual. Thus, since the anatomy of its nervous system is largely hard-wired, C. elegans is a useful model for identifying genes that control neuronal morphogenesis and connectivity.
We use live imaging and forward genetics, to directly observe neuronal morphogenesis and to find the relevant genes. Recently, we saw that sensory neurons get their shapes by an unusual mechanism: a neuron is born at the nose, “drops anchor,” and then crawls away, stretching its dendrite out behind it. We isolated mutants that disrupt anchor components, causing dendrites to be too short. Our long-term goal is to understand how the complete sensory anatomy of this simple animal is encoded, with an eye to eventually learning how genes encode the basic rules that wire our own, much more complex, brains.
For a complete listing of publications click here.
Last Update: 11/7/2013