scholarly journals Ribosomal protein L32 of Saccharomyces cerevisiae influences both the splicing of its own transcript and the processing of rRNA.

1997 ◽  
Vol 17 (4) ◽  
pp. 1959-1965 ◽  
Author(s):  
J Vilardell ◽  
J R Warner

Ribosomal protein L32 of Saccharomyces cerevisiae binds to and regulates the splicing and the translation of the transcript of its own gene. Selecting for mutants deficient in the regulation of splicing, we have identified a mutant form of L32 that no longer binds to the transcript of RPL32 and therefore does not regulate its splicing. The mutation is the deletion of an isoleucine residue from a highly conserved hydrophobic domain near the middle of L32. The mutant protein supports growth, at a reduced rate, and is found at normal levels in mature ribosomes. However, in cells homozygous for the mutant gene, the rate of processing of the ribosomal RNA component of the 60S ribosomal subunit is severely reduced, leading to an insufficiency of 60S subunits. L32 must be considered a remarkable protein. Composed of only 104 amino acids, it appears to interact with three distinct RNA molecules to influence three different elements of RNA processing and function in three different locations of the cell: the processing of pre-rRNA in the nucleolus, the splicing of the RPL32 transcript in the nucleus, and the translation of the spliced RPL32 mRNA in the cytoplasm.

1993 ◽  
Vol 13 (5) ◽  
pp. 2835-2845
Author(s):  
M Deshmukh ◽  
Y F Tsay ◽  
A G Paulovich ◽  
J L Woolford

Ribosomal protein L1 from Saccharomyces cerevisiae binds 5S rRNA and can be released from intact 60S ribosomal subunits as an L1-5S ribonucleoprotein (RNP) particle. To understand the nature of the interaction between L1 and 5S rRNA and to assess the role of L1 in ribosome assembly and function, we cloned the RPL1 gene encoding L1. We have shown that RPL1 is an essential single-copy gene. A conditional null mutant in which the only copy of RPL1 is under control of the repressible GAL1 promoter was constructed. Depletion of L1 causes instability of newly synthesized 5S rRNA in vivo. Cells depleted of L1 no longer assemble 60S ribosomal subunits, indicating that L1 is required for assembly of stable 60S ribosomal subunits but not 40S ribosomal subunits. An L1-5S RNP particle not associated with ribosomal particles was detected by coimmunoprecipitation of L1 and 5S rRNA. This pool of L1-5S RNP remained stable even upon cessation of 60S ribosomal subunit assembly by depletion of another ribosomal protein, L16. Preliminary results suggest that transcription of RPL1 is not autogenously regulated by L1.


Genetics ◽  
1993 ◽  
Vol 135 (3) ◽  
pp. 719-730
Author(s):  
A G Paulovich ◽  
J R Thompson ◽  
J C Larkin ◽  
Z Li ◽  
J L Woolford

Abstract The Saccharomyces cerevisiae CRY1 gene encodes the 40S ribosomal subunit protein rp59 and confers sensitivity to the protein synthesis inhibitor cryptopleurine. A yeast strain containing the cry1-delta 1::URA3 null allele is viable, cryptopleurine sensitive (CryS), and expresses rp59 mRNA, suggesting that there is a second functional CRY gene. The CRY2 gene has been isolated from a yeast genomic library cloned in bacteriophage lambda, using a CRY1 DNA probe. The DNA sequence of the CRY2 gene contains an open reading frame encoding ribosomal protein 59 that differs at five residues from rp59 encoded by the CRY1 gene. The CRY2 gene was mapped to the left arm of chromosome X, centromere-proximal to cdc6 and immediately adjacent to ribosomal protein genes RPS24A and RPL46. Ribosomal protein 59 is an essential protein; upon sporulation of a diploid doubly heterozygous for cry1-delta 2::TRP1 cry2-delta 1::LEU2 null alleles, no spore clones containing both null alleles were recovered. Several results indicate that CRY2 is expressed, but at lower levels than CRY1: (1) Introduction of CRY2 on high copy plasmids into CryR yeast of genotype cry1 CRY2 confers a CryS phenotype. Transformation of these CryR yeast with CRY2 on a low copy CEN plasmid does not confer a CryS phenotype. (2) Haploids containing the cry1-delta 2::TRP1 null allele have a deficit of 40S ribosomal subunits, but cry2-delta 1::LEU2 strains have wild-type amounts of 40S ribosomal subunits. (3) CRY2 mRNA is present at lower levels than CRY1 mRNA. (4) Higher levels of beta-galactosidase are expressed from a CRY1-lacZ gene fusion than from a CRY2-lacZ gene fusion. Mutations that alter or eliminate the last amino acid of rp59 encoded by either CRY1 or CRY2 result in resistance to cryptopleurine. Because CRY2 (and cry2) is expressed at lower levels than CRY1 (and cry1), the CryR phenotype of cry2 mutants is only expressed in strains containing a cry1-delta null allele.


2012 ◽  
Vol 32 (16) ◽  
pp. 3228-3241 ◽  
Author(s):  
R. Babiano ◽  
M. Gamalinda ◽  
J. L. Woolford ◽  
J. de la Cruz

2009 ◽  
Vol 8 (11) ◽  
pp. 1792-1802 ◽  
Author(s):  
Lixia Jia ◽  
Jasvinder Kaur ◽  
Rosemary A. Stuart

ABSTRACT The Oxa1 protein plays a central role in facilitating the cotranslational insertion of the nascent polypeptide chains into the mitochondrial inner membrane. Mitochondrially encoded proteins are synthesized on matrix-localized ribosomes which are tethered to the inner membrane and in physical association with the Oxa1 protein. In the present study we used a chemical cross-linking approach to map the Saccharomyces cerevisiae Oxa1-ribosome interface, and we demonstrate here a close association of Oxa1 and the large ribosomal subunit protein, MrpL40. Evidence to indicate that a close physical and functional relationship exists between MrpL40 and another large ribosomal protein, the Mrp20/L23 protein, is also provided. MrpL40 shares sequence features with the bacterial ribosomal protein L24, which like Mrp20/L23 is known to be located adjacent to the ribosomal polypeptide exit site. We propose therefore that MrpL40 represents the Saccharomyces cerevisiae L24 homolog. MrpL40, like many mitochondrial ribosomal proteins, contains a C-terminal extension region that bears no similarity to the bacterial counterpart. We show that this C-terminal mitochondria-specific region is important for MrpL40's ability to support the synthesis of the correct complement of mitochondrially encoded proteins and their subsequent assembly into oxidative phosphorylation complexes.


1985 ◽  
Vol 5 (7) ◽  
pp. 1655-1659
Author(s):  
D D Rhoads ◽  
D J Roufa

The Chinese hamster ovary (CHO) cell 40S ribosomal subunit protein S14 provides a unique opportunity to investigate an important mammalian housekeeping gene and its mRNA and protein products. The S14 gene appears to be single copy, and CHO cell S14 mutants have been isolated as emetine-resistant (emtB) clones in tissue culture. Thus, S14 is the only mammalian ribosomal protein whose gene structure and function are amenable to straightforward genetic and biochemical analysis. Recently, we isolated a wild-type Chinese hamster lung cell cDNA clone, pCS14-1, including an almost complete copy of the ribosomal protein S14 message (N. Nakamichi, D. D. Rhoads, and D. J. Roufa, J. Biol. Chem. 258: 13236-13242, 1983). Here we describe comparable cDNAs from wild-type and emtB CHO cells. We report both mRNA and polypeptide sequences of the wild-type and mutant ribosomal protein transcripts. As a consequence of the genetic methods used to obtain our emetine-resistant mutants, the emtB S14 cDNAs differ from wild-type cDNA by single-base changes. Physical and chemical features of polypeptides encoded by the cDNAs are consistent with well-characterized S14 protein polymorphisms. The three emtB mutations analyzed affect two adjacent arginine codons within the very basic S14 carboxyl region, indicating a significant role for this portion of the protein in the function and architecture of the mammalian 40S ribosomal subunit.


1985 ◽  
Vol 5 (7) ◽  
pp. 1655-1659 ◽  
Author(s):  
D D Rhoads ◽  
D J Roufa

The Chinese hamster ovary (CHO) cell 40S ribosomal subunit protein S14 provides a unique opportunity to investigate an important mammalian housekeeping gene and its mRNA and protein products. The S14 gene appears to be single copy, and CHO cell S14 mutants have been isolated as emetine-resistant (emtB) clones in tissue culture. Thus, S14 is the only mammalian ribosomal protein whose gene structure and function are amenable to straightforward genetic and biochemical analysis. Recently, we isolated a wild-type Chinese hamster lung cell cDNA clone, pCS14-1, including an almost complete copy of the ribosomal protein S14 message (N. Nakamichi, D. D. Rhoads, and D. J. Roufa, J. Biol. Chem. 258: 13236-13242, 1983). Here we describe comparable cDNAs from wild-type and emtB CHO cells. We report both mRNA and polypeptide sequences of the wild-type and mutant ribosomal protein transcripts. As a consequence of the genetic methods used to obtain our emetine-resistant mutants, the emtB S14 cDNAs differ from wild-type cDNA by single-base changes. Physical and chemical features of polypeptides encoded by the cDNAs are consistent with well-characterized S14 protein polymorphisms. The three emtB mutations analyzed affect two adjacent arginine codons within the very basic S14 carboxyl region, indicating a significant role for this portion of the protein in the function and architecture of the mammalian 40S ribosomal subunit.


1993 ◽  
Vol 13 (5) ◽  
pp. 2835-2845 ◽  
Author(s):  
M Deshmukh ◽  
Y F Tsay ◽  
A G Paulovich ◽  
J L Woolford

Ribosomal protein L1 from Saccharomyces cerevisiae binds 5S rRNA and can be released from intact 60S ribosomal subunits as an L1-5S ribonucleoprotein (RNP) particle. To understand the nature of the interaction between L1 and 5S rRNA and to assess the role of L1 in ribosome assembly and function, we cloned the RPL1 gene encoding L1. We have shown that RPL1 is an essential single-copy gene. A conditional null mutant in which the only copy of RPL1 is under control of the repressible GAL1 promoter was constructed. Depletion of L1 causes instability of newly synthesized 5S rRNA in vivo. Cells depleted of L1 no longer assemble 60S ribosomal subunits, indicating that L1 is required for assembly of stable 60S ribosomal subunits but not 40S ribosomal subunits. An L1-5S RNP particle not associated with ribosomal particles was detected by coimmunoprecipitation of L1 and 5S rRNA. This pool of L1-5S RNP remained stable even upon cessation of 60S ribosomal subunit assembly by depletion of another ribosomal protein, L16. Preliminary results suggest that transcription of RPL1 is not autogenously regulated by L1.


Chromosoma ◽  
1997 ◽  
Vol 105 (7-8) ◽  
pp. 523-531
Author(s):  
Rob W. van Nues ◽  
Jaap Venema ◽  
Rudi J. Planta ◽  
Hendrik A. Raué

RNA Biology ◽  
2020 ◽  
Vol 17 (9) ◽  
pp. 1261-1276
Author(s):  
Sara Martín-Villanueva ◽  
José Fernández-Fernández ◽  
Olga Rodríguez-Galán ◽  
Julia Fernández-Boraita ◽  
Eduardo Villalobo ◽  
...  

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