Background：

Regulatory subunit of the ATP-dependent NoRC-1 and NoRC-5 ISWI chromatin remodeling complexes， which form ordered nucleosome arrays on chromatin and facilitate access to DNA during DNA-templated processes such as DNA replication， transcription， and repair. Both complexes regulate the spacing of nucleosomes along the chromatin and have the ability to slide mononucleosomes to the center of a DNA template. Directly stimulates the ATPase activity of SMARCA5 in the NoRC-5 ISWI chromatin remodeling complex. The NoRC-1 ISWI chromatin remodeling complex has a lower ATP hydrolysis rate than the NoRC-5 ISWI chromatin remodeling complex. Within the NoRC-5 ISWI chromatin remodeling complex， mediates silencing of a fraction of rDNA by recruiting histone-modifying enzymes and DNA methyltransferases， leading to heterochromatin formation and transcriptional silencing (By similarity. In the complex， it plays a central role by being recruited to rDNA and by targeting chromatin modifying enzymes such as HDAC1， lea