Welcome to the IUMS 2022 Interactive Program
The congress will officially run on Central European Summer Time (UTC+2) - Rotterdam Time
To convert the congress times to your local time Click Here
The viewing of sessions and E-Posters cannot be accessed from this congress calendar.
All content is accessible only via the IUMS Virtual Platform.
- T. Berben (Netherlands)
Extremophiles and Archaea 01
- S. Albers (Germany)
Abstract
Abstract Body
Archaea use a rotary structure for movement, the archaellum. This structure is homologous to type IV pili and requires ATP for assembly and rotation. Interestingly, many archaea have obtained the chemotaxis system for sensing stimuli and respond to these by changing the rotation direction of the archaellum. However, as the archaellum motor is different from the bacterial flagellum motor, archaea evolved several adaptor proteins so that phosphorylated CheY can initiate a switch in the rotation direction. We have recently solved the structures of archaeal CheY and a unique adaptor protein CheF and can show how these confer the signal to the archaellum motor.
Extremophiles and Archaea
- U. Gophna (Israel)
Abstract
Abstract Body
CRISPR-Cas systems provide heritable acquired immunity against viruses to archaea and bacteria. Cas3 is a CRISPR-associated protein that is common to all Type I systems, possesses both nuclease and helicase activities, and is responsible for degradation of invading DNA. Involvement of Cas3 in DNA repair had been suggested in the past, but later abandoned when the role of CRISPR-Cas as an adaptive immune system was realized. Here we show that in the halophilic archaeon Haloferax volcanii a cas3 deletion mutant exhibits increased resistance to DNA damage compared with the wild-type strain, but its ability to recover quickly from such damage is reduced. A similar damage-resistance phenotype was observed in the naturally CRISPR-less Haloferax gibbonsii strain. Analysis of cas3 mutants revealed that the helicase domain of the protein is the one responsible for DNA damage sensitivity. Epistasis analysis indicated that cas3, operated with mre11 and rad50 in the microhomology-mediated end-joining pathway of DNA repair, while co-immunoprecipitation shows interaction with RadA, the major DNA recombinase in archaea. These results demonstrate that Cas proteins not only affect DNA repair but have become an integral part of the cellular response to DNA damage.