The specific endoribonuclease activity of small nuclear and cytoplasmic α-RNPs

Abstract

For the first time small nuclear ribonucleoprotein particles (α-RNP) tightly bound to chromatin as well as cytoplasmic α-RNP are shown to possess strong and regulated endonuclease activity specific for mRNAs and hnRNAs. The enzymatic nature of this activity is confirmed, and the optimal conditions detected. This RNase activity is controlled by the action of a differentiating stimulus, dimethylsulfoxide, in human K562 cells. Small α-RNP involvement in the coordinated control of stability of pre-messenger RNA and messenger RNA molecules is suggested.