GRIFFITH LAB @ BRANDEIS
NEUROTRANSMITTER IDENTITY
The neurotransmitter type of a neuron was once thought to be singular and immutable. It became clear several decades ago, however, that many neurons have both a small transmitter and neuropeptides. More recently, an increasing number of cases of neurons with multiple small transmitters have been reported, and active regulation of this cardinal feature of identity has been suggested to be an important form of plasticity.
We have generated a comprehensive set of genetic tools to mark and manipulate specific subtypes of vesicles. These tools will allow us to follow neurotransmitter phenotypes in particular neurons over time and decipher the rules of transmitter plasticity.
CRISPR-engineered tools for visualizing and manipulating specific types of synaptic vesicles
We have generated a set of CRISPR alleles for the VAChT, VGAT, VGluT, VMAT, IA-2 and CAPS genes that give us the ability to tag or remove each protein in a cell-specific manner. We have also made split-GFP versions to detect interactions with other vesicular proteins.
Functional studies of dense core vesicles
Using CRISPR-engineered alleles of IA-2 and CAPS, we are elucidating the roles of dense core vesicles in behavior and circuit formation. We have also used Mass Spec and biochemical methods to identify proteins that interact with IA-2 and CAPS.
Neurotransmitter plasticity
The neurotransmitter identity of a neuron can be plastic. Examples of changes in transmitter phenotype during development or in response to alteration in neuronal activity in the mature nervous system have been documented in many organisms. Using tagged alleles of vesicular transporters, we have shown miR-190 can reversibly control cholinergic phenotype in a large number of adult neurons.