Related Experiment Videos
Guide-independent DNA cleavage by archaeal Argonaute from Methanocaldococcus jannaschii
Adrian Zander1, Sarah Willkomm1, Sapir Ofer2
1Department of Microbiology &Archaea Centre, University of Regensburg, Regensburg 93053, Germany.
Abstract:
Prokaryotic Argonaute proteins acquire guide strands derived from invading or mobile genetic elements, via an unknown pathway, to direct guide-dependent cleavage of foreign DNA. Here, we report that Argonaute from the archaeal organism Methanocaldococcus jannaschii (MjAgo) possesses two modes of action: the canonical guide-dependent endonuclease activity and a non-guided DNA endonuclease activity. The latter allows MjAgo to process long double-stranded DNAs, including circular plasmid DNAs and genomic DNAs. Degradation of substrates in a guide-independent fashion primes MjAgo for subsequent rounds of DNA cleavage. Chromatinized genomic DNA is resistant to MjAgo degradation, and recombinant histones protect DNA from cleavage in vitro. Mutational analysis shows that key residues important for guide-dependent target processing are also involved in guide-independent MjAgo function. This is the first characterization of guide-independent cleavage activity for an Argonaute protein potentially serving as a guide biogenesis pathway in a prokaryotic system.
Related Concept Videos
Maxam-Gilbert Sequencing
Challenges of the Maxam-Gilbert Method
The...
DNA Isolation
Restriction Enzymes
The host bacteria protect their own genomic DNA from these enzymes by methylating these sites. Some...
Homologous Recombination
Conservation of Protein Domains Over Different Proteins
A limited set of protein domains often duplicate and recombine during evolution. These domains can be organized in different combinations to...
Diversity of Archaea III