cI and CI

Abedon, Stephen T.

doi:10.5281/zenodo.20173633

🔬 cI and CI

The phage lambda (λ) repressor gene and protein.

by Stephen T. Abedon Ph.D. Steve Abedon, Ph.D., has taught well over 100 individual classes and ~10 individual courses (including introductory biology, microbiology, physiology, biochemistry, etc.) over his 30+ years as a college professor. He has over 150 publications, including multiple monographs, and is ranked in the top 1 or 2 percent among researchers of all disciplines worldwide. His research focuses on bacteriophage biology and phage therapy. (abedon.1@osu.edu)

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About this entry: cI and CI is one of a growing set of phage biology and phage therapy terms defined here. For more phage terms, see Abedon, S.T. (2025). Phage Therapy Annotated Glossary. Preprints.org. 10.20944/preprints202508.0347.v1
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cI and CI: The phage lambda (λ) repressor gene and protein.

Discussion

Phages with mutations in gene cI are unable to lysogenize. They are also unable to productively infect existing phage λ lysogens. The "c" stands for "clear" as in clear plaque mutant.

For reviews providing discussion of the lambda phage repressor, see Little (2005), Ptashne (2004), etc.

External links

Wikipedia Google PubMed Google Scholar

References

Little, J.W. (2005). Lysogeny, prophage induction, and lysogenic conversion. In: Waldor, M.K., Friedman, D.I. & Adhya, S.L. (eds.) Phages: Their Role in Bacterial Pathogenesis and Biotechnology. ASM Press, Washington, DC.
Ptashne, M. (2004). A Genetic Switch: Phage Lambda Revisited. 3rd ed. Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY.

How to cite this page

Abedon, S.T. (2026). Phage Terms. https://terms.phage.org · 10.5281/zenodo.20173633

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[1] Little, J.W. (2005). Lysogeny, prophage induction, and lysogenic conversion. In: Waldor, M.K., Friedman, D.I. & Adhya, S.L. (eds.) Phages: Their Role in Bacterial Pathogenesis and Biotechnology. ASM Press, Washington, DC.

[2] Ptashne, M. (2004). A Genetic Switch: Phage Lambda Revisited. 3rd ed. Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY.