RNase P from bacteria. Substrate recognition and function of the protein subunit

1996 ◽  
Vol 22 (2-3) ◽  
pp. 99-109 ◽  
Author(s):  
Leif A. Kirsebom ◽  
Agust�n Vioque
2005 ◽  
Vol 25 (15) ◽  
pp. 6546-6558 ◽  
Author(s):  
Vilius Stribinskis ◽  
Hong-Chen Heyman ◽  
Steven R. Ellis ◽  
Marlene C. Steffen ◽  
Nancy C. Martin

ABSTRACT Rpm2p, a protein subunit of yeast mitochondrial RNase P, has another function that is essential in cells lacking the wild-type mitochondrial genome. This function does not require the mitochondrial leader sequence and appears to affect transcription of nuclear genes. Rpm2p expressed as a fusion protein with green fluorescent protein localizes to the nucleus and activates transcription from promoters containing lexA-binding sites when fused to a heterologous DNA binding domain, lexA. The transcriptional activation region of Rpm2p contains two leucine zippers that are required for transcriptional activation and are conserved in the distantly related yeast Candida glabrata. The presence of a mitochondrial leader sequence does not prevent a portion of Rpm2p from locating to the nucleus, and several observations suggest that the nuclear location and transcriptional activation ability of Rpm2p are physiologically significant. The ability of RPM2 alleles to suppress tom40-3, a temperature-sensitive mutant of a component of the mitochondrial import apparatus, correlates with their ability to transactivate the reporter genes with lexA-binding sites. In cells lacking mitochondrial DNA, Rpm2p influences the levels of TOM40, TOM6, TOM20, TOM22, and TOM37 mRNAs, which encode components of the mitochondrial import apparatus, but not that of TOM70 mRNA. It also affects HSP60 and HSP10 mRNAs that encode essential mitochondrial chaperones. Rpm2p also increases the level of Tom40p, as well as Hsp60p, but not Atp2p, suggesting that some, but not all, nucleus-encoded mitochondrial components are affected.


Genetics ◽  
2001 ◽  
Vol 158 (2) ◽  
pp. 573-585
Author(s):  
Vilius Stribinskis ◽  
Guo-Jian Gao ◽  
Steven R Ellis ◽  
Nancy C Martin

Abstract RPM2 is a Saccharomyces cerevisiae nuclear gene that encodes the protein subunit of mitochondrial RNase P and has an unknown function essential for fermentative growth. Cells lacking mitochondrial RNase P cannot respire and accumulate lesions in their mitochondrial DNA. The effects of a new RPM2 allele, rpm2-100, reveal a novel function of RPM2 in mitochondrial biogenesis. Cells with rpm2-100 as their only source of Rpm2p have correctly processed mitochondrial tRNAs but are still respiratory deficient. Mitochondrial mRNA and rRNA levels are reduced in rpm2-100 cells compared to wild type. The general reduction in mRNA is not reflected in a similar reduction in mitochondrial protein synthesis. Incorporation of labeled precursors into mitochondrially encoded Atp6, Atp8, Atp9, and Cytb protein was enhanced in the mutant relative to wild type, while incorporation into Cox1p, Cox2p, Cox3p, and Var1p was reduced. Pulse-chase analysis of mitochondrial translation revealed decreased rates of translation of COX1, COX2, and COX3 mRNAs. This decrease leads to low steady-state levels of Cox1p, Cox2p, and Cox3p, loss of visible spectra of aa3 cytochromes, and low cytochrome c oxidase activity in mutant mitochondria. Thus, RPM2 has a previously unrecognized role in mitochondrial biogenesis, in addition to its role as a subunit of mitochondrial RNase P. Moreover, there is a synthetic lethal interaction between the disruption of this novel respiratory function and the loss of wild-type mtDNA. This synthetic interaction explains why a complete deletion of RPM2 is lethal.


Biochemistry ◽  
2009 ◽  
Vol 48 (6) ◽  
pp. 1293-1304 ◽  
Author(s):  
Jian Cao ◽  
Hang Xu ◽  
Hong Zhao ◽  
Weimin Gong ◽  
Debra Dunaway-Mariano

1996 ◽  
Vol 22 (2-3) ◽  
pp. 111-114
Author(s):  
Hideaki Shiraishi ◽  
Yoshiro Shimura

1996 ◽  
Vol 16 (7) ◽  
pp. 3429-3436 ◽  
Author(s):  
V Stribinskis ◽  
G J Gao ◽  
P Sulo ◽  
Y L Dang ◽  
N C Martin

Rpm2p is a protein subunit of Saccharomyces cerevisiae yeast mitochondrial RNase P, an enzyme which removes 5' leader sequences from mitochondrial tRNA precursors. Precursor tRNAs accumulate in strains carrying a disrupted allele of RPM2. The resulting defect in mitochondrial protein synthesis causes petite mutants to form. We report here that alteration in the biogenesis of Rpm1r, the RNase P RNA subunit, is another consequence of disrupting RPM2. High-molecular-weight transcripts accumulate, and no mature Rpm1r is produced. Transcript mapping reveals that the smallest RNA accumulated is extended on both the 5' and 3' ends relative to mature Rpm1r. This intermediate and other longer transcripts which accumulate are also found as low-abundance RNAs in wild-type cells, allowing identification of processing events necessary for conversion of the primary transcript to final products. Our data demonstrate directly that Rpm1r is transcribed with its substrates, tRNA met f and tRNAPro, from a promoter located upstream of the tRNA met f gene and suggest that a portion also originates from a second promoter, located between the tRNA met f gene and RPM1. We tested the possibility that precursors accumulate because the RNase P deficiency prevents the removal of the downstream tRNAPro. Large RPM1 transcripts still accumulate in strains missing this tRNA. Thus, an inability to process cotranscribed tRNAs does not explain the precursor accumulation phenotype. Furthermore, strains with mutant RPM1 genes also accumulate precursor Rpm1r, suggesting that mutations in either gene can lead to similar biogenesis defects. Several models to explain precursor accumulation are presented.


2016 ◽  
Vol 27 (7) ◽  
pp. 1154-1169 ◽  
Author(s):  
Alyshia Newhart ◽  
Sara Lawrence Powers ◽  
Prashanth Krishna Shastrula ◽  
Isabel Sierra ◽  
Lucy M. Joo ◽  
...  

In mammals, histone H3.3 is a critical regulator of transcription state change and heritability at both euchromatin and heterochromatin. The H3.3-specific chaperone, DAXX, together with the chromatin-remodeling factor, ATRX, regulates H3.3 deposition and transcriptional silencing at repetitive DNA, including pericentromeres and telomeres. However, the events that precede H3.3 nucleosome incorporation have not been fully elucidated. We previously showed that the DAXX-ATRX-H3.3 pathway regulates a multi-copy array of an inducible transgene that can be visualized in single living cells. When this pathway is impaired, the array can be robustly activated. H3.3 is strongly recruited to the site during activation where it accumulates in a complex with transcribed sense and antisense RNA, which is distinct from the DNA/chromatin. This suggests that transcriptional events regulate H3.3 recruited to its incorporation sites. Here we report that the nucleolar RNA proteins Rpp29, fibrillarin, and RPL23a are also components of this H3.3/RNA complex. Rpp29 is a protein subunit of RNase P. Of the other subunits, POP1 and Rpp21 are similarly recruited suggesting that a variant of RNase P regulates H3.3 chromatin assembly. Rpp29 knockdown increases H3.3 chromatin incorporation, which suggests that Rpp29 represses H3.3 nucleosome deposition, a finding with implications for epigenetic regulation.


Sign in / Sign up

Export Citation Format

Share Document