Ph.D. candidate Kayley Janssen passed her doctoral defense

On November 17, 2017, Kayley H. Janssen successfully defended her thesis titled, "Post-transcriptional regulation of virulence factors in Pseudomonas aeruginosa”.  Kayley Jannsen


It all began in 1989 when Kayley was born in Denver, Colorado. Her family soon realized that the great state of Iowa was calling as the perfect place to raise twins, stock a freezer with sweet corn, and cultivate a love for science. Kayley grew up in the small town of Williamsburg, IA where she learned to play the clarinet, how to block a spike in volleyball, and explore the natural ecosystem of eastern Iowa. Her family moved to western New York for the first two years of high school. There, Kayley fell in love with biology thanks to a wonderful teacher and his children’s book about allosteric regulation and enzyme kinetics. After a short stint in western NY, her family relocated to Laramie, Wyoming where Kayley graduated as a Plainsman and attended the University of Wyoming in hopes of being a cowgirl.

In the fall of 2007, Kayley began majoring in oboe performance and music education, but was unimpressed by her ability to make reeds, match pitch, and dictate music. Thankfully, Kayley had taken an introductory biology course, which she was eager to get to three days a week at 8 am. With the help of her professor, she decided to pursue an education in the molecular biology department. She put away the sheet music and traded it in for a pipette.

Kayley pursued several research projects during her undergraduate career at Wyoming including the diversity of planctomycetes in algal blooms and the effect of coal fly ash on microbial growth. After graduating in 2011 she took a post-baccalaureate position at Rocky Mountain Labs working with Dr. Steve Porcella in the Genomics Unit. There she developed an appreciation for host-pathogen interactions, bioinformatics, and RNA.

Kayley enrolled in the graduate program in the Department of Microbiology in August of 2013 and joined the lab of Dr. Tim Yahr. She has conducted research on post-transcriptional regulation of virulence factors in Pseudomonas aeruginosa and has earned her certificate in bioinformatics.

Outside of the lab Kayley enjoys spending time with her husband, Brian. They love cooking new recipes and sharing meals with their friends and family. Kayley likes to spend time outside either taking their two dogs Banjo and Archie on adventures, camping, or hiking and loves lifting weights, yoga, and running. She recently completed three half-marathons, qualifying her as a half-fanatic.



Pseudomonas aeruginosa is a Gram-negative bacterium capable of causing infections in immunocompromised individuals. The ability of P. aeruginosa to cause a variety of infections is due in part to the large array of virulence factors it produces. The focus of my thesis was to characterize post-transcriptional regulation of virulence factors by RsmA, RsmF, and Hfq.

RsmA and RsmF are RNA-bind proteins that regulate gene expression at the post-transcriptional level. My first goal was to determine the mechanistic basis for differential binding that is observed by RsmA and RsmF. I found that RsmF has more restrictive requirements for binding RNA targets and requires at least two binding sites for high affinity binding.

Hfq is an RNA chaperone that stabilizes sRNA and/or facilitates their binding to mRNA targets. P. aeruginosa Hfq regulates about 5% of the genome and has a role in post-transcriptional control of T3SS in many Gram-negative bacteria. My second goal was to determine the mechanism of Hfq control of P. aeruginosa T3SS. I have identified that Hfq regulates T3SS gene expression by both a direct and indirect mechanism.

Tuesday, November 21, 2017