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John Rawls

Associate Professor
Molecular Genetics and Microbiology
Research Interest: 
Developmental biology
Research Summary: 
Microbial regulation of intestinal physiology; adipose tissue development and metabolic disease.
Research Description: 

Animal physiology is directed by complex interactions between factors encoded in the animal’s genome and those encountered in their environment. The impact of these interactions on animal health is most evident in the intestine, where digestion and absorption of dietary nutrients occur in the presence of complex communities of microorganisms (microbiota). Interactions between diet, microbiota, and animal hosts regulate immune and metabolic homeostasis and also contribute to a spectrum of human diseases, including the inflammatory bowel diseases, obesity, and malnutrition. Our research interests are focused on understanding how environmental factors such as the intestinal microbiota and diet interact with host genome-encoded processes to influence host physiology and pathophysiology. We are using the zebrafish as a vertebrate model system for this research. The small size and optical transparency of the zebrafish facilitate high-resolution in vivo imaging as well as genetic and chemical manipulations that complement the technical limitations of mammalian models. Extensive anatomic, physiologic, and genomic homologies between zebrafish and mammals permit translation of insights gained in zebrafish into advances in human medicine. To facilitate our research, we have developed methods for rearing zebrafish under germ-free conditions and for introducing selected microbial communities and sterilized diets into germ-free fish. We are currently using zebrafish and mouse models to investigate how microbial communities are assembled in the intestine and how microbes and dietary nutrients regulate host metabolism and immunity. We have also established methods for in vivo analysis of adipose tissues in zebrafish, and we are using that experimental platform to elucidate the mechanisms underlying adipose tissue physiology and obesity-associated metabolic disease. The overall objective of our work is to improve our understanding of vertebrate physiology as a complex and dynamic integration of genome-encoded and environmental factors, which is expected to yield new strategies for promoting health in humans and other animals.

Animals in a bacterial world, a new imperative for the life sciences.
McFall-Ngai M, Hadfield MG, Bosch TC, Carey HV, Domazet-Lošo T, Douglas AE, Dubilier N, Eberl G, Fukami T, Gilbert SF, Hentschel U, King N, Kjelleberg S, Knoll AH, Kremer N, Mazmanian SK, Metcalf JL, Nealson K, Pierce NE, Rawls JF, Reid A, Ruby EG, Rumpho M, Sanders JG, Tautz D, Wernegreen JJ.
Proc Natl Acad Sci U S A. 2013. 110:3229-36.

Microbiota regulate intestinal absorption and metabolism of fatty acids in the zebrafish.
Semova I, Carten JD, Stombaugh J, Mackey LC, Knight R, Farber SA, Rawls JF.
Cell Host Microbe. 2012. 12:277-88.

Intronic cis-regulatory modules mediate tissue-specific and microbial control of angptl4/fiaf transcription.
Camp JG, Jazwa AL, Trent CM, Rawls JF.
PLoS Genet. 2012. 8:e1002585.

Microbial colonization induces dynamic temporal and spatial patterns of NF-κB activation in the zebrafish digestive tract.
Kanther M, Sun X, Mühlbauer M, Mackey LC, Flynn EJ, Bagnat M, Jobin C, Rawls JF.
Gastroenterology. 2011. 141:197-207.

Ontogeny and nutritional control of adipogenesis in zebrafish (Danio rerio).
Flynn EJ, Trent CM, Rawls JF.
J Lipid Res. 2009. 50:1641-52.