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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Temperature-sensitive mutant | 3/3 | https://en.wikipedia.org/wiki/Temperature-sensitive_mutant | reference | science, encyclopedia | 2026-05-05T07:16:55.194576+00:00 | kb-cron |
=== Bacteriophage === An infection of an Escherichia coli host cell by a bacteriophage (phage) T4 temperature -ensitive (TS) conditionally lethal mutant at a high restrictive temperature generally leads to no phage growth. However, a co-infection under restrictive conditions with two TS mutants defective in different genes generally leads to robust growth because of intergenic complementation. The discovery of TS mutants of phage T4 and the employment of such mutants in complementation tests contributed to the identification of many of the genes in this organism. Because multiple copies of a polypeptide specified by a gene often form multimers, mixed infections with two different TS mutants defective in the same gene often lead to mixed multimers and partial restoration of function, a phenomenon referred to as intragenic complementation. Intragenic complementation of TS mutants defective in the same gene can provide information on the structural organization of the multimer. The growth of phage TS mutants under partially restrictive conditions has been used to identify the functions of genes. Thus, genes employed in the repair of DNA damages were identified, as well as genes affecting genetic recombination. For example, growing a TS DNA repair mutant at an intermediate temperature will allow some progeny phage to be produced. However, if that TS mutant is irradiated with UV light, its survival will be more strongly reduced compared to the reduction of survival of irradiated wild-type phage T4. Conditional lethal mutants able to grow at high temperatures but unable to grow at low temperatures were also isolated in phage T4. These cold-sensitive mutants defined a discrete set of genes, some of which had been previously identified by other types of conditional lethal mutants.
== References ==
Febvre C, Goldblatt C, El-Sabaawi R. Thermal performance of ecosystems: Modeling how physiological responses to temperature scale up in communities. Journal of Theoretical Biology. 2024;585:N.PAG. doi:10.1016/j.jtbi.2024.111792 Edelsparre, A. H., Fitzpatrick, M. J., Saastamoinen, M., & Teplitsky, C. (2024). Evolutionary adaptation to climate change. Evolution letters, 8(1), 1–7. https://doi.org/10.1093/evlett/qrad070 Hilfiker, A., Nothiger, R. The temperature-sensitive mutation vir ts(virilizer) identifies a new gene involved in sex determination of Drosophila . Roux's Arch Dev Biol 200, 240–248 (1991). https://doi.org/10.1007/BF00241293 Gonsalvez, J. L., Burghes, A. H., & Kunkel, L. M. (2020). Temperature-sensitive spinal muscular atrophy-causing point mutations destabilize the SMN protein at elevated temperatures. Disease Models & Mechanisms, 13(5), dmm043307. https://doi.org/10.1242/dmm.043307 Tan, G., Chen, M., Foote, C., & Tan, C. (2009). Temperature-sensitive mutations made easy: Generating conditional mutations by using temperature-sensitive inteins. Proceedings of the National Academy of Sciences, 106(24), 9155-9160. https://doi.org/10.1073/pnas.0900235106