PMID: 186453Nov 25, 1976

Purification and characterization of an endoribonuclease from nucleoplasm and nucleoli of HeLa cells

The Journal of Biological Chemistry
C N Kwan


An endoribonuclease has been isolated from HeLa cell nuclei. Approximately 70% of the enzyme appears to be nucleolar bound; 30% is in the nucleoplasm. Studies of the purified enzyme reveal that the enzyme is an endonuclease of estimated molecular weight 16,000. It produces oligonucleotides bearing 5'-phosphate end groups. The enzyme degrades poly(C) and poly(U), as well as rRNA and heterogeneous nuclear RNA, Poly(A), double-stranded RNA, and DNA are not cleaved. The enzyme is heat-labile and is inhibited by 10mM Mg2+ and 50 mM NaCl. The enzyme is probably distinct from previously described nuclear endonucleases.

Related Concepts

Cell Fractionation
Cell Nucleolus
Cell Nucleus
HeLa Cells
Phosphoric diester hydrolase
Poly C
Alkaline Ribonuclease

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