RNA



An active precursor in assembly of yeast nuclear ribonuclease P


CHATCHAWAN  SRISAWAT  a1, FELICIA  HOUSER-SCOTT  a1, EDOUARD  BERTRAND  a2, SHAOHUA  XIAO  a1, ROBERT H.  SINGER  a3 and DAVID R.  ENGELKE  a1 c1
a1 Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109-0606, USA
a2 Institut de Genetique Moleculaire de Montpellier, IFR 24-Centre National de la Recherche Scientifique UMR 5535, 34000 Montpellier, France
a3 Department of Anatomy and Structural Biology and Cell Biology, Albert Einstein College of Medicine, New York, New York 10461, USA

Abstract

The RNA–protein subunit assembly of nuclear RNase P was investigated by specific isolation and characterization of the precursor and mature forms of RNase P using an RNA affinity ligand. Pre-RNase P was as active in pre-tRNA cleavage as mature RNase P, although it contained only seven of the nine proteins found in mature RNase P. Pop3p and Rpr2p were not required for maturation of the RPR1 RNA subunit and virtually absent from pre-RNase P, implying that they are dispensable for pre-tRNA substrate recognition and cleavage. The RNase P subunit assembly is likely to occur in the nucleolus, where both precursor and mature forms of RNase P RNA are primarily localized. The results provide insight into assembly of nuclear RNase P, and suggest pre-tRNA substrate recognition is largely determined by the RNA subunit.

(Received July 11 2002)
(Revised July 25 2002)
(Accepted July 31 2002)


Key Words: RNase P; RPR2; POP3; RPR1.

Correspondence:
c1 Reprint requests to: David R. Engelke, Department of Biological Chemistry, University of Michigan, 3200 MSRB III, 1150 W. Medical Center Drive, Ann Arbor, Michigan 48109-0606, USA; e-mail: engelke@umich.edu