Richard W. Carthew, Ph.D.

Research

Our group studies the mechanism and function of gene silencing by small RNAs and differentiation and patterning of the eye in the model system Drosophila melanogaster. We have searched for mutants that are unable to mount a normal RNAi response. From this search, we identified many genes that are important for siRNAs and miRNAs to work properly. Those genes that we have cloned are also found in the human genome, and indeed, they turn out to be important for gene silencing in humans as well. We have also been investigating the chemistry of RNAi.

In addition, we study the patterning of photoreceptor neurons. Color vision is achieved through photoreceptors containing opsin photopigments with different wavelength specificity. These photopigments are expressed in mutually exclusive patterns in the compound eye of Drosophila. This implies there is a process for choosing a given opsin gene and transcriptionally repressing all others. The restricted expression of a transcription factor called Prospero in R7 neurons is critical for their development as photoreceptors with unique wavelength sensitivity. We use molecular and genetic approaches to identify the signaling pathways responsible for the elaboration of this system.