microLife Poster Prize: Wendy Geslewitz

Congratulations to Wendy Geslewitz, PhD Candidate at the Laboratory of Dr. Hank Seifert, Department of Microbiology and Immunology Northwestern University (USA) for winning a Poster Prize at the Gordon Research Conference on Microbial Adhesion and Signal Transduction (GRC-MAST). This conference took place at Salve Regina University (USA) on 16 – 21 July 2023.

This award is sponsored by our journal microLife and as well as receiving a cash prize, we interviewed Wendy to find out more about her prize winning research:

What has been your route through microbiology thus far?

Prior to entering graduate school, I hadn’t had much experience working in microbiology. I was unsure what research I wanted to pursue in my PhD, but I always enjoyed learning about bacteria and all the cool stuff they do—not just in the realm of pathogenesis. I got my feet wet in Bacteriology through a few rotations and decided to stick with this field. The lab I ultimately joined delves into bacterial genetics, and the problem-solving involved in genetic research reminded me of the fun challenges that come from working on puzzles. Reading about the exciting new research and creative uses of bacteria in many realms of medicine has invigorated my own work and pushed me to succeed. Despite the often-frustrating challenges, I can confidently say my experience in microbiology has been fun. I am also reassured that I will never be bored learning about bacteria even as I accumulate more knowledge. Throughout my time in this field, I’ve seen that the oft-repeated proverb continues to hold true: “the more you know, the less you realize you know.”

Could you provide a brief and simple overview of the topic your oral presentation covers?

Broadly speaking, our lab studies the genetics of Neisseria gonorrhoeae (Gc). Although several tools exist to manipulate the genetics of this bacteria, it did not have a CRISPR system. Our collaborator, Dr. Yan Zhang from University of Michigan, had been characterizing the Type I-C CRISPR system in the commensal Neisseria lactamica (Nla) and worked with us to transfer an IPTG-inducible Nla CRISPR system into in the Gc chromosome. We generated a CRISPR-interference (CRISPRi) system in Gc by excluding the Cas3 nuclease-helicase. The CRISPR machinery will still be guided to a specific site on the genome via a gene-specific spacer, but instead of cutting the DNA, it will sit on the DNA and block RNA Polymerase from binding and transcribing the gene-of-interest. The use of this system results in a genetic knockdown instead of a knockout. One of the advantages of CRISPRi is its use in studying essential genes that cannot be mutated.

Interestingly, Gc encodes many essential genes that are predicted to be phage-related. Despite the clear importance of these phage genes, very little work has been done to study the function of these genes and whether they can produce a functional phage. We decided to use the Nla CRISPRi system to knockdown NGO0479, a predicted phage repressor essential for Gc viability. Not only did NGO0479 knockdown result in a significant rise in transcript abundance of other predicted phage genes, but excitingly, we were able to isolate tailed phage particles from the supernatants of these bacteria.

What encouraged you to perform research in this area of microbiology?

This project has been fun because it has been part-tool development and part-hypothesis driven. Engineered CRISPR systems have proven to be so useful in all types of organisms, so hopefully, having a functional system working in Gc will give the Neisseria community a helpful tool to answer some previously unexplored questions. Gc also has ~800 predicted essential genes, many of which have unknown functions due to the inability to generate mutations. CRISPRi has allowed us to evaluate the importance of these genes, particularly with phage. Furthermore, CRISPR and phage are both hot topics in bacteriology, so being able to combine both these fields in Gc has been a strong motivation for this project.

What do you see as the next steps in this area of research?

We have a lot of cool avenues to explore with this project. Our next steps include determining the specific type of phage the NGO0479 represses, what conditions facilitate phage induction and bacterial lysis, the permissive host range of this phage, and the consequences of carrying these phage islands. I am very excited to see how this project progresses.

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