Skip to main content
Explore URMC

James S. Butler, Ph.D.

Contact Information

Phone Numbers

Office: (585) 275-7921

Fax: (585) 473-9573

Research Labs

Faculty Appointments



One goal of the work in the laboratory is a clear understanding of the mechanisms that ensure the proper expression of messenger RNAs in eukaryotes. The research focuses on a nuclear mRNA surveillance pathway in eukaryotes that destroys aberrant RNAs before they exit the nucleus. Central to this pathway is a conserved complex of proteins called the exosome that degrades RNA molecules that fail to undergo post-transcriptional processing reactions such as polyadenylation and splicing. A major unanswered question addressed by the research is what components of the nuclear exosome and the associated TRAMP complex are required for the processing and degradation of RNAs in the nucleus. This RNA surveillance system guards against the formation of defective RNA-protein complexes that have toxic effects on cell growth and proliferation. Previous studies identified Rrp6p, a nuclear exoribonuclease component of the exosome and showed that it plays a critical role in degrading aberrant RNAs in the nucleus. More recent evidence indicates that a second complex called TRAMP plays a key role in activating RNA substrates for degradation by the nuclear exosome. Experiments underway in the lab aim to (i) identify the components of the TRAMP complex required for enhancement of Rrp6p activity, (ii) elucidate the role that TRAMP and Rrp6p play in a general and a specific pathway for mRNA degradation.

A second project focuses the public health challenge caused by the resurgence of tuberculosis and the spread of antibiotic resistant strains of the causative agent, Mycobacterium tuberculosis. Tuberculosis kills nearly 2 million people each year and estimates put the worldwide population of infected individuals at nearly 2 billion. A majority of these people (90%) carries latent, asymptomatic infections that reactivate causing disease and spread of M. tuberculosis to uninfected individuals. The latent phase and the slow growth rate of M. tuberculosis limit the effectiveness of existing antibiotics. One approach to treatment of tuberculosis would be to design drugs that inhibit the establishment of the latent phase or reactivate growth under conditions allowing aggressive treatment of the infection. Uncharacterized toxin-antitoxin systems in M. tuberculosis may play a role in the establishment and maintenance of the latent phase of infection. Work in the laboratory is designed to (i) test the hypothesis that activation of these systems induces a static metabolic state in cells, (ii) identify the molecular targets of the toxins and (iii) determine the impact of the loss of Pin-toxin function on M. tuberculosis survival during hypoxia-induced latency. These studies will lay the groundwork for a thorough analysis of the molecular biology of these toxin-antitoxin systems with the goal of designing therapeutic approaches to the treatment of latent M. tuberculosis infections.



BS | Univ Wisconsin-Madison

PhD | Univ of Illinois-Urbana

Post-doctoral Training & Residency

1987 - 1989
University of Rochester, Postdoc., Molec. Biol.

1984 - 1987
Institut de Biologie Physico-chimique, Paris


Graduate Alumni Award
Sponsor: URMC
Location: URMC

Outstanding Program Director Award
Sponsor: URMC
Location: URMC

1983 - 1986
NIH - CNRS Postdoctoral Fellowship

NIH - INSERM Postdoctoral Fellowship - Declined

1980 - 1983
NIH Predoctoral Traineeship in Biochemistry

VIEW ALL expand_more


Journal Articles

Walling LR, Butler JS. "Toxins targeting transfer RNAs: Translation inhibition by bacterial toxin-antitoxin systems." Wiley interdisciplinary reviews. RNA.. 2019 Jan 0; 10(1):e1506. Epub 2018 Sep 16.

Walling LR, Butler JS. "Homologous VapC Toxins Inhibit Translation and Cell Growth by Sequence-Specific Cleavage of tRNA." Journal of bacteriology.. 2018 Feb 1; 200(3)Epub 2018 Jan 10.

Walling LR, Butler JS. "Structural Determinants for Antitoxin Identity and Insulation of Cross Talk between Homologous Toxin-Antitoxin Systems." Journal of bacteriology.. 2016 Dec 15; 198(24):3287-3295. Epub 2016 Nov 18.