What is CRISPR gene?

you mean CRISPR/cas9 system

CRISPR/cas9 is defense system found in , consists of a protein called cas9 and the CRISPR locus

CRISPR locus crispr means clustered regular interspaced short palindromic repeats, it consists of short repeats and between them spacers, theses spacer sequences are complementary to some sequences that could be found in , due to exposure to bacteriophage viruses, it's like keeping a copy of the viruse DNA in the bacteria's DNA so when the same virus or phage attack the bacteria again, it can protect it self

cas9 crispr associated protein 9, is a RNA guided DNA endonucluease, that can cleave foreign DNA sequences from viruses once they inject them inside the bacteria by a guided complementary RNA sequence that the bacteria keep as a copy in the crispr locus

the crispr cas9 system is an immunity defense system that protect the bacteria from the infection of phages and mean while scientist are hoping to use it in gene editing in humans