DOI: 10.1101/486738Dec 4, 2018Paper

Cas4 nucleases can effect specific integration of CRISPR spacers

BioRxiv : the Preprint Server for Biology
Zhufeng ZhangNan Peng

Abstract

CRISPR-Cas systems incorporate short DNA fragments from invasive genetic elements into host CRISPR arrays in order to generate host immunity.Recently, we demonstrated that the Csa3a regulator protein triggers CCN PAM-dependent CRISPR spacer acquisition in the subtype I-A CRISPR-Cas system of Sulfolobus islandicus. However, the mechanisms underlying specific protospacer selection and spacer insertion remained unclear. Here, we demonstrate that two Cas4 family proteins (Cas4 and Csa1) have essential roles (a) in recognizing the 5' PAM and 3' nucleotide motif of protospacers and (b) in determining both the spacer length and its orientation. Furthermore, we identify uncovered amino acid residues of the Cas4 proteins that facilitate these functions. Overexpression of the Cas4 and Csa1 proteins, and also of an archaeal virus-encoded Cas4 protein, resulted in strongly reduced adaptation efficiency and the formers yielded a high incidence of PAM-dependent atypical spacer integration, or of PAM-independent spacer integration. We further demonstrated that, in the plasmid challenging experiments, overexpressed Cas4-mediated defective spacer acquisition, in turn, potentially enabled targeted DNA to escape subtype I-A CRISPR-Cas interferenc...Continue Reading

Related Concepts

DNA
Plasmids
Virus
Adaptation
Subtype (Attribute)
Nuclease
Research Study
Archaeal Viruses
Protein Overexpression
Orientation (spatial)

Related Feeds

CRISPR Ribonucleases Deactivation

CRISPR-Cas system enables the editing of genes to create or correct mutations. This feed focuses on mechanisms that underlie deactivation of CRISPR ribonucleases. Here is the latest research.

Virology & CRISPR

This feed focuses on the virology of CRISPR and its use in developing CRISPR-Cas systems. Discover the latest research here.

BioRxiv & MedRxiv Preprints

BioRxiv and MedRxiv are the preprint servers for biology and health sciences respectively, operated by Cold Spring Harbor Laboratory. Here are the latest preprint articles (which are not peer-reviewed) from BioRxiv and MedRxiv.

CRISPR Genome Editing & Therapy (Preprints)

CRISPR-Cas system enables the editing of genes to create or correct mutations. This feed focuses on the application of this system for gene editing and therapy in human diseases.

CRISPR for Genome Editing

Genome editing technologies enable the editing of genes to create or correct mutations. Clustered regularly interspaced short palindromic repeats (CRISPR) are DNA sequences in the genome that are recognized and cleaved by CRISPR-associated proteins (Cas). Here is the latest research on the use of CRISPR-Cas system in gene editing.

CRISPR for Genome Editing (Preprints)

Genome editing technologies enable the editing of genes to create or correct mutations. Clustered regularly interspaced short palindromic repeats (CRISPR) are DNA sequences in the genome that are recognized and cleaved by CRISPR-associated proteins (Cas). Here are the latest preprints on the use of CRISPR-Cas system in gene editing.

CRISPR (general)

Clustered regularly interspaced short palindromic repeats (CRISPR) are DNA sequences in the genome that are recognized and cleaved by CRISPR-associated proteins (Cas). CRISPR-Cas system enables the editing of genes to create or correct mutations. Discover the latest research on CRISPR here.