TY - JOUR
T1 - Localization in the nucleolus and coiled bodies of protein subunits of the ribonucleoprotein ribonuclease P
AU - Jarrous, Nayef
AU - Wolenski, Joseph S.
AU - Wesolowski, Donna
AU - Lee, Christopher
AU - Altman, Sidney
PY - 1999/8/9
Y1 - 1999/8/9
N2 - The precise location of the tRNA processing ribonucleoprotein ribonuclease P (RNase P) and the mechanism of its intranuclear distribution have not been completely delineated. We show that three protein subunits of human RNase P (Rpp), Rpp14, Rpp29 and Rpp38, are found in the nucleolus and that each can localize a reporter protein to nucleoli of cells in tissue culture. In contrast to Rpp38, which is uniformly distributed in nucleoli, Rpp14 and Rpp29 are confined to the dense fibrillar component. Rpp29 and Rpp38 possess functional, yet distinct domains required for subnucleolar localization. The subunit Rpp14 lacks such a domain and appears to be dependent on a piggy-back process to reach the nucleolus. Biochemical analysis suggests that catalytically active RNase P exists in the nucleolus. We also provide evidence that Rpp29 and Rpp38 reside in coiled bodies, organelles that are implicated in the biogenesis of several other small nuclear ribonucleoproteins required for processing of precursor mRNA. Because some protein subunits of RNase P are shared by the ribosomal RNA processing ribonucleoprotein RNase MRP, these two evolutionary related holoenzymes may share common intranuclear localization and assembly pathways to coordinate the processing of tRNA and rRNA precursors.
AB - The precise location of the tRNA processing ribonucleoprotein ribonuclease P (RNase P) and the mechanism of its intranuclear distribution have not been completely delineated. We show that three protein subunits of human RNase P (Rpp), Rpp14, Rpp29 and Rpp38, are found in the nucleolus and that each can localize a reporter protein to nucleoli of cells in tissue culture. In contrast to Rpp38, which is uniformly distributed in nucleoli, Rpp14 and Rpp29 are confined to the dense fibrillar component. Rpp29 and Rpp38 possess functional, yet distinct domains required for subnucleolar localization. The subunit Rpp14 lacks such a domain and appears to be dependent on a piggy-back process to reach the nucleolus. Biochemical analysis suggests that catalytically active RNase P exists in the nucleolus. We also provide evidence that Rpp29 and Rpp38 reside in coiled bodies, organelles that are implicated in the biogenesis of several other small nuclear ribonucleoproteins required for processing of precursor mRNA. Because some protein subunits of RNase P are shared by the ribosomal RNA processing ribonucleoprotein RNase MRP, these two evolutionary related holoenzymes may share common intranuclear localization and assembly pathways to coordinate the processing of tRNA and rRNA precursors.
KW - Coiled body
KW - Nucleolus
KW - RNase mitochondrial RNA processing
KW - Ribonuclease P
KW - tRNA
UR - http://www.scopus.com/inward/record.url?scp=0033538829&partnerID=8YFLogxK
U2 - 10.1083/jcb.146.3.559
DO - 10.1083/jcb.146.3.559
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C2 - 10444065
AN - SCOPUS:0033538829
SN - 0021-9525
VL - 146
SP - 559
EP - 571
JO - Journal of Cell Biology
JF - Journal of Cell Biology
IS - 3
ER -