scholarly journals Basic Domains Target Protein Subunits of the RNase MRP Complex to the Nucleolus Independently of Complex Association

2001 ◽  
Vol 12 (11) ◽  
pp. 3680-3689 ◽  
Author(s):  
Hans van Eenennaam ◽  
Annemarie van der Heijden ◽  
Rolf J. R. J. Janssen ◽  
Walther J. van Venrooij ◽  
Ger J. M. Pruijn

The RNase MRP and RNase P ribonucleoprotein particles both function as endoribonucleases, have a similar RNA component, and share several protein subunits. RNase MRP has been implicated in pre-rRNA processing and mitochondrial DNA replication, whereas RNase P functions in pre-tRNA processing. Both RNase MRP and RNase P accumulate in the nucleolus of eukaryotic cells. In this report we show that for three protein subunits of the RNase MRP complex (hPop1, hPop4, and Rpp38) basic domains are responsible for their nucleolar accumulation and that they are able to accumulate in the nucleolus independently of their association with the RNase MRP and RNase P complexes. We also show that certain mutants of hPop4 accumulate in the Cajal bodies, suggesting that hPop4 traverses through these bodies to the nucleolus. Furthermore, we characterized a deletion mutant of Rpp38 that preferentially associates with the RNase MRP complex, giving a first clue about the difference in protein composition of the human RNase MRP and RNase P complexes. On the basis of all available data on nucleolar localization sequences, we hypothesize that nucleolar accumulation of proteins containing basic domains proceeds by diffusion and retention rather than by an active transport process. The existence of nucleolar localization sequences is discussed.

1998 ◽  
Vol 9 (9) ◽  
pp. 2407-2422 ◽  
Author(s):  
Miroslav Dundr ◽  
Mark O.J. Olson

Previous studies showed that components implicated in pre-rRNA processing, including U3 small nucleolar (sno)RNA, fibrillarin, nucleolin, and proteins B23 and p52, accumulate in perichromosomal regions and in numerous mitotic cytoplasmic particles, termed nucleolus-derived foci (NDF) between early anaphase and late telophase. The latter structures were analyzed for the presence of pre-rRNA by fluorescence in situ hybridization using probes for segments of pre-rRNA with known half-lives. The NDF did not contain the short-lived 5′-external transcribed spacer (ETS) leader segment upstream from the primary processing site in 47S pre-rRNA. However, the NDF contained sequences from the 5′-ETS core, 18S, internal transcribed spacer 1 (ITS1), and 28S segments and also had detectable, but significantly reduced, levels of the 3′-ETS sequence. Northern analyses showed that in mitotic cells, the latter sequences were present predominantly in 45S-46S pre-rRNAs, indicating that high-molecular weight processing intermediates are preserved during mitosis. Two additional essential processing components were also found in the NDF: U8 snoRNA and hPop1 (a protein component of RNase MRP and RNase P). Thus, the NDF appear to be large complexes containing partially processed pre-rRNA associated with processing components in which processing has been significantly suppressed. The NDF may facilitate coordinated assembly of postmitotic nucleoli.


2010 ◽  
Vol 68 (14) ◽  
pp. 2469-2480 ◽  
Author(s):  
Sandy Mattijssen ◽  
Ella R. Hinson ◽  
Carla Onnekink ◽  
Pia Hermanns ◽  
Bernhard Zabel ◽  
...  
Keyword(s):  
Rnase P ◽  

2005 ◽  
Vol 33 (3) ◽  
pp. 479-481 ◽  
Author(s):  
S.C. Walker ◽  
T.V. Aspinall ◽  
J.M.B. Gordon ◽  
J.M. Avis

In yeast, RNase MRP (mitochondrial RNA processing), a ribonucleoprotein precursor rRNA processing enzyme, possesses one putatively catalytic RNA and ten protein subunits and is highly related to RNase P. Structural analysis of the MRP RNA provides data that closely match a previous secondary-structure model derived from phylogenetic analysis, with the exception of an additional stem. This stem occupies an equivalent position to the P7 stem of RNase P RNA and its inclusion confers on MRP RNA a greater similarity to the core P RNA structure. In vivo studies indicate that the P7-like stem can form, but is not a part of, the active enzyme structure. Stem formation would increase RNA stability in the absence of proteins and our alternative structure may be a valid intermediate species in RNase MRP assembly. Further ongoing studies of this enzyme reveal an extensive network of interactions between subunits and a probable central role for the Pop1, Pop4 and Pop7 subunits.


2001 ◽  
Vol 276 (34) ◽  
pp. 31635-31641 ◽  
Author(s):  
Hans van Eenennaam ◽  
Dorien Lugtenberg ◽  
Judith H. P. Vogelzangs ◽  
Walther J. van Venrooij ◽  
Ger J. M. Pruijn

1996 ◽  
Vol 15 (21) ◽  
pp. 5936-5948 ◽  
Author(s):  
Z. Lygerou ◽  
H. Pluk ◽  
W. J. van Venrooij ◽  
B. Séraphin

1999 ◽  
Vol 146 (3) ◽  
pp. 559-572 ◽  
Author(s):  
Nayef Jarrous ◽  
Joseph S. Wolenski ◽  
Donna Wesolowski ◽  
Christopher Lee ◽  
Sidney Altman

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 piggyback 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.


2010 ◽  
Vol 38 (12) ◽  
pp. 4052-4066 ◽  
Author(s):  
Katherine L. D. Hands-Taylor ◽  
Luigi Martino ◽  
Renée Tata ◽  
Jeffrey J. Babon ◽  
Tam T. Bui ◽  
...  
Keyword(s):  
Rnase P ◽  

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