Abstract
Halophilic Haloferax volcanii is the most studied archaeon, and serves as a tool for researchers to study cellular evolution, shape transitions, and various other unique biologies that the archaeal domain of life perform. Although H. volcanii serves as a model organism for archaeal cell biology, nearly one third of its genes are annotated as hypothetical and have no functional prediction or clear homologs outside the archaeal domain (Kirkland et al. 2008). In this thesis, we generate a CRISPRi library that targets the expression of the majority of H. volcanii genes. With cells carrying the CRISPRi library under growth selection, we were able to parse essential from nonessential genes, thus aiding our ability to draw the first hierarchical map of important genes regardless of their putative annotation. From our screenings, we identified 96 essential genes (-2 log₂-fold change ≥), representing 3% of the targets in the genome. Of these genes, half are hypothetical or of no known function. Our findings constitute a vast list of gene candidates to be further investigated.