LIS - Legume Information System
Information about legume traits for crop improvement
CicerMine
v5.1.0.3
Cicer data from the Legume Information System
v5.1.0.3
Cicer data from the Legume Information System
| Type | Family |
| Description | The CRISPR-Cas system is a prokaryotic defense mechanism against foreign genetic elements. The key elements of this defense system are the Cas proteins and the CRISPR RNA. Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) are a family of DNA direct repeats separated by regularly sized non-repetitive spacer sequences that are found in most bacterial and archaeal genomes [ ]. CRISPRs appear to provide acquired resistance against mobile genetic elements (viruses, transposable elements and conjugative plasmids). CRISPR clusters contain sequences complementary to antecedent mobile elements and target invading nucleic acids. CRISPR clusters are transcribed and processed into CRISPR RNA (crRNA). The defense reaction is divided into three stages. In the adaptation stage, the invader DNA is cleaved, and a piece of it is selected to be integrated as a new spacer into the CRISPR locus, where it is stored as an identity tag for future attacks by this invader. During the second stage (the expression stage), the CRISPR RNA (pre-crRNA) is transcribed and subsequently processed into the mature crRNAs. In the third stage (the interference stage), Cas proteins, together with crRNAs, identify and degrade the invader [ , , ].The CRISPR-Cas systems have been sorted into three major classes. In CRISPR-Cas types I and III, the mature crRNA is generally generated by a member of the Cas6 protein family. Whereas in system III the Cas6 protein acts alone, in some class I systems it is part of a complex of Cas proteins known as Cascade (CRISPR-associated complex for antiviral defense). The Cas6 protein is an endoribonuclease necessary for crRNA production whereas the additional Cas proteins that form the Cascade complex are needed for crRNA stability [ ]. This entry represents members of the family of Cas2, one of the first four protein families found to be associated with prokaryotic genomes containing multiple CRISPR elements. CRISPR systems protect against invasive nucleic acid sequences, including phage. Cas2 proteins have been characterised as either endoribonuclease (for ssRNA) or endodeoxyribonuclease (for dsDNA), depending on the system to which the Cas2 belongs [ ]. The cas genes usually are found near the palindromic repeats. It's worth noting that there is a distinct branch of the Cas2 family showing a very low level of sequence identity [ , ].The structural subunit of Cas2, belongs to the VapD family of interferases. The interferase catalytic site is intact in the majority of the Cas2 proteins but is disrupted in some, and is not required for spacer acquisition [ , ].This entry also includes the endoribonuclease VapD [ ]. These proteins are defined by a conserved region found at the N terminus of the VapD protein []. |
| Short Name | Virulence_VapD/CRISPR_Cas2 |
