PAM-repeat associations and spacer selection preferences in single and co-occurring CRISPR-Cas systems.

ABSTRACT:

Background

The adaptive CRISPR-Cas immune system stores sequences from past invaders as spacers in CRISPR arrays and thereby provides direct evidence that links invaders to hosts. Mapping CRISPR spacers has revealed many aspects of CRISPR-Cas biology, including target requirements such as the protospacer adjacent motif (PAM). However, studies have so far been limited by a low number of mapped spacers in the database.

Results

By using vast metagenomic sequence databases, we map approximately one-third of more than 200,000 unique CRISPR spacers from a variety of microbes and derive a catalog of more than two hundred unique PAM sequences associated with specific CRISPR-Cas subtypes. These PAMs are further used to correctly assign the orientation of CRISPR arrays, revealing cons

SUBMITTER: Vink JNA 

PROVIDER: S-EPMC8482600 | biostudies-literature | 2021 Sep

REPOSITORIES: biostudies-literature