Adaptation by Type V-A and V-B CRISPR-Cas Systems Demonstrates Conserved Protospacer Selection Mechanisms Between Diverse CRISPR-Cas Types.

Adaptation of clustered regularly interspaced short palindromic repeats (CRISPR) arrays is a crucial process responsible for the unique, adaptive nature of CRISPR-Cas immune systems. The acquisition of new CRISPR spacers from mobile genetic elements has previously been studied for several types of CRISPR-Cas systems. In this study, we used a high-throughput sequencing approach to characterize CRISPR adaptation of the type V-A system from and the type V-B system from .

Mechanism for Cas4-assisted directional spacer acquisition in CRISPR-Cas.

Prokaryotes adapt to challenges from mobile genetic elements by integrating spacers derived from foreign DNA in the CRISPR array. Spacer insertion is carried out by the Cas1-Cas2 integrase complex. A substantial fraction of CRISPR-Cas systems use a Fe-S cluster containing Cas4 nuclease to ensure that spacers are acquired from DNA flanked by a protospacer adjacent motif (PAM) and inserted into the CRISPR array unidirectionally, so that the transcribed CRISPR RNA can guide target searching in a PAM-dependent manner.

Cas4-Cas1 Is a Protospacer Adjacent Motif-Processing Factor Mediating Half-Site Spacer Integration During CRISPR Adaptation.

The immunization of bacteria and archaea against invading viruses via CRISPR adaptation is critically reliant on the efficient capture, accurate processing, and integration of CRISPR spacers into the host genome. The adaptation proteins Cas1 and Cas2 are sufficient for successful spacer acquisition in some CRISPR-Cas systems. However, many CRISPR-Cas systems additionally require the Cas4 protein for efficient adaptation.

Correction: Wachs, S., et al. Associations between Witnessing and Perpetrating Online Hate in Eight Countries: The Buffering Effects of Problem-Focused Coping. 2019, , 3992.

The authors wish to add the following corrections to their paper published in the International Journal of Environmental Research and Public Health [...

A Routine Activity Approach to Understand Cybergrooming Victimization Among Adolescents from Six Countries.

Little attention has been given academically to empirically tested theoretical frameworks that aim at measuring the risk of adolescents falling victim to cybergrooming. To this end, we have applied the routine activity theory (RAT) to investigate whether exposure to motivated offenders (PC/laptop ownership and Internet access in one's own bedroom), capable guardianship (parental mediation strategies of Internet use), and target suitability (adolescents' online disclosure of private information) might predict cybergrooming victimization among adolescents. Using data from a cross-sectional survey of 5,938 adolescents from Germany, India, South Korea, Spain, Thailand, and the United States, ranging in age from 12 to 18 ( = 14.