MCRS1,also named INO80Q,MSP58 or p78,is a nucleolar protein expressed in the very early S phase. It modulates the transcription repressor activity of DAXX by recruiting it to the nucleolus. MCRS1 is also present on polyribosomes of synaptoneurosome as a novel RNA-binding protein to activate the rRNA transcription. The forkhead-associated domain of MCRS1 is involved in association with centrosomal protein Nde1,comprising a component of the centrosome and taking an essential role in viability. Its isoform MCRS2 might be a linker between telomere maintenance and cell-cycle regulation by interacting with LPTS/PinX1,a telomerase-inhibitory protein. MCRS1 is detected by Western blot as a highly modified protein at 78 kDa and minor bands at about 62 and 55 kDa.