TY - JOUR
T1 - Temperature-dependent hypermutational phenotype in recA mutants of thermus thermophilus HB27
AU - Castán, Pablo
AU - Casares, Lorena
AU - Barbé, Jordi
AU - Berenguer, José
PY - 2003/8/1
Y1 - 2003/8/1
N2 - The recA gene from Thermus thermophilus HB27 was cloned and engineered to obtain insertion (recA::kat) and deletion (ΔrecA) derivatives. Transcription of recA in this extreme thermophile was induced by mitomycin C, leading to the synthesis of a monocistronic mRNA. This DNA damage-mediated induction was dependent on the integrity of recA. In addition to UV sensitivity, the recA mutants of T. thermophilus showed severe pleiotropic defects, ranging from irregular nucleoid condensation and segregation to a dramatic reduction in viability during culture. An increase in the frequency of both carotenoidless and auxotrophic mutants within surviving cells of the ΔrecA strain indicated a high mutation rate. As RecA is not required for plasmid transformation, we have used the α-lacZ gene fragment and the ampicillin resistance gene from Escherichia coli as passenger reporters to confirm such high mutation rates. Our data support the idea that the absence of RecA results in a hypermutational phenotype in T. thermophilus. Furthermore, a direct relationship is deduced between the growth temperature and mutation rate, which finally has a deleterious effect on cell survival in the absence of RecA.
AB - The recA gene from Thermus thermophilus HB27 was cloned and engineered to obtain insertion (recA::kat) and deletion (ΔrecA) derivatives. Transcription of recA in this extreme thermophile was induced by mitomycin C, leading to the synthesis of a monocistronic mRNA. This DNA damage-mediated induction was dependent on the integrity of recA. In addition to UV sensitivity, the recA mutants of T. thermophilus showed severe pleiotropic defects, ranging from irregular nucleoid condensation and segregation to a dramatic reduction in viability during culture. An increase in the frequency of both carotenoidless and auxotrophic mutants within surviving cells of the ΔrecA strain indicated a high mutation rate. As RecA is not required for plasmid transformation, we have used the α-lacZ gene fragment and the ampicillin resistance gene from Escherichia coli as passenger reporters to confirm such high mutation rates. Our data support the idea that the absence of RecA results in a hypermutational phenotype in T. thermophilus. Furthermore, a direct relationship is deduced between the growth temperature and mutation rate, which finally has a deleterious effect on cell survival in the absence of RecA.
U2 - https://doi.org/10.1128/JB.185.16.4901-4907.2003
DO - https://doi.org/10.1128/JB.185.16.4901-4907.2003
M3 - Article
VL - 185
SP - 4901
EP - 4907
JO - Journal of Bacteriology
JF - Journal of Bacteriology
SN - 0021-9193
ER -