The CRISPR-Cas system is an adaptive immune system of prokaryotes, and is widely distributed in the chromosomes of most archaea and many bacteria, to defend against the invasion of foreign genetic elements. CRISPR-Cas systems are not only found in chromosomes but also widely distributed in mobile genetics ...
The CRISPR-Cas system is an adaptive immune system of prokaryotes, and is widely distributed in the chromosomes of most archaea and many bacteria, to defend against the invasion of foreign genetic elements. CRISPR-Cas systems are not only found in chromosomes but also widely distributed in mobile genetics elements including bacteriophages and plasmids. The system consists of a CRISPR array, comprising short direct repeats, separated by short variable DNA sequences (called “spacers”) acquired from foreign genetic elements, and is flanked by various genes of CRISPR-associated proteins (Cas). Cas proteins are highly diverse and are involved in the different stages of CRISPR activity. Based on the Cas proteins structure, function, and genetic organization, CRISPR-Cas systems can be classified into at least two classes and six types, however, the existence of CRISPR-Cas systems with novel types and functions are yet to be identified and characterized. Even though CRISPR-Cas is known as defense system of prokaryotes, they are also involved in different non-defense roles, including bacterial biofilm formation, regulation of collective behavior or quorum sensing, and pathogenicity. Therefore, it is important to understand the role of CRISPR-Cas systems in bacterial and archaeal physiology along with their defense mechanisms.
If their function is to protect bacteria from the invasion of mobile genetic elements then what is the function of CRISPR-Cas systems present in the invading mobile genetic elements? It is also believed that CRISPR-Cas systems may be involved in bacterial physiological functions. What are the functions they participate in other than immunity? Additionally, it is well known that CRISPR-Cas systems carry many self-targeted spacers. What is the reason for this? Research that sheds light on the distribution, diversity, and function of the CRISPR-Cas systems will help to increase our understanding of the questions raised above.
We are inviting you to contribute to this Special Issue with either Original Research or Review articles that shed light on the following potential areas:
• Identification and characterization of CRISPR-Cas systems
• Distribution of CRISPR-Cas systems in bacteria and archaea
• Genetic and functional diversity of CRISPR-Cas
• Functions of CRISPR-Cas other than immunity
• Identification and functions of CRSPR-Cas systems associated with mobile genetic elements
• Role of self-targeted spacers on CRISPR
Keywords:
CRISPR-Cas systems, Bacteria, Archaea, Mobile Genetic elements.
Important Note:
All contributions to this Research Topic must be within the scope of the section and journal to which they are submitted, as defined in their mission statements. Frontiers reserves the right to guide an out-of-scope manuscript to a more suitable section or journal at any stage of peer review.