@article{nethery_hidalgo-cantabrana_roberts_barrangou_2022, title={CRISPR-based engineering of phages for in situ bacterial base editing}, volume={119}, ISSN={["1091-6490"]}, url={https://doi.org/10.1073/pnas.2206744119}, DOI={10.1073/pnas.2206744119}, abstractNote={
            Investigation of microbial gene function is essential to the elucidation of ecological roles and complex genetic interactions that take place in microbial communities. While microbiome studies have increased in prevalence, the lack of viable in situ editing strategies impedes experimental progress, rendering genetic knowledge and manipulation of microbial communities largely inaccessible. Here, we demonstrate the utility of phage-delivered CRISPR-Cas payloads to perform targeted genetic manipulation within a community context, deploying a fabricated ecosystem (EcoFAB) as an analog for the soil microbiome. First, we detail the engineering of two classical phages for community editing using recombination to replace nonessential genes through Cas9-based selection. We show efficient engineering of T7, then demonstrate the expression of antibiotic resistance and fluorescent genes from an engineered λ prophage within an
            Escherichia coli
            host. Next, we modify λ to express an APOBEC-1-based cytosine base editor (CBE), which we leverage to perform C-to-T point mutations guided by a modified Cas9 containing only a single active nucleolytic domain (nCas9). We strategically introduce these base substitutions to create premature stop codons in-frame, inactivating both chromosomal (
            lacZ
            ) and plasmid-encoded genes (mCherry and ampicillin resistance) without perturbation of the surrounding genomic regions. Furthermore, using a multigenera synthetic soil community, we employ phage-assisted base editing to induce host-specific phenotypic alterations in a community context both in vitro and within the EcoFAB, observing editing efficiencies from 10 to 28% across the bacterial population. The concurrent use of a synthetic microbial community, soil matrix, and EcoFAB device provides a controlled and reproducible model to more closely approximate in situ editing of the soil microbiome.
          }, number={46}, journal={PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA}, author={Nethery, Matthew A. and Hidalgo-Cantabrana, Claudio and Roberts, Avery and Barrangou, Rodolphe}, year={2022}, month={Nov} }
 @article{roberts_nethery_barrangou_2022, title={Functional characterization of diverse type I-F CRISPR-associated transposons}, volume={11}, ISSN={["1362-4962"]}, url={https://doi.org/10.1093/nar/gkac985}, DOI={10.1093/nar/gkac985}, abstractNote={Abstract}, journal={NUCLEIC ACIDS RESEARCH}, author={Roberts, Avery and Nethery, Matthew A. and Barrangou, Rodolphe}, year={2022}, month={Nov} }
 @article{pan_morovic_hidalgo-cantabrana_roberts_walden_goh_barrangou_2022, title={Genomic and epigenetic landscapes drive CRISPR-based genome editing in Bifidobacterium}, volume={119}, ISSN={["1091-6490"]}, url={https://doi.org/10.1073/pnas.2205068119}, DOI={10.1073/pnas.2205068119}, abstractNote={Bifidobacteriumis a commensal bacterial genus ubiquitous in the human gastrointestinal tract, which is associated with a range of health benefits. The advent of CRISPR-based genome editing technologies provides opportunities to investigate the genetics of important bacteria and transcend the lack of genetic tools in bifidobacteria to study the basis for their health-promoting attributes. Here, we repurpose the endogenous type I-G CRISPR-Cas system and adopt an exogenous CRISPR base editor for genome engineering inB. animalissubsp.lactis,demonstrating that both genomic and epigenetic contexts drive editing outcomes across strains. We reprogrammed the endogenous type I-G system to screen for naturally occurring large deletions up to 27 kb and to generate a 500-bp deletion intetWto abolish tetracycline resistance. A CRISPR-cytosine base editor was optimized to install C•G-to-T•A amber mutations to resensitize multipleB. lactisstrains to tetracycline. Remarkably, we uncovered epigenetic patterns that are distributed unevenly amongB. lactisstrains, despite their genomic homogeneity, that may contribute to editing efficiency variability. Insights were also expanded toBifidobacterium longumsubsp.infantisto emphasize the broad relevance of these findings. This study highlights the need to develop individualized CRISPR-based genome engineering approaches for distinct bacterial strains and opens avenues for engineering of next generation probiotics.}, number={30}, journal={PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA}, author={Pan, Meichen and Morovic, Wesley and Hidalgo-Cantabrana, Claudio and Roberts, Avery and Walden, Kimberly K. O. and Goh, Yong Jun and Barrangou, Rodolphe}, year={2022}, month={Jul} }