Table 1.
Genes that affect nonsense readthrough in S. cerevisiae
| Gene* | Protein | Function** | Effect on nonsense readthrough*** |
|---|---|---|---|
| ACT1 | Act1 | Actin | Nonsense suppressor96 |
| DCP1 | Dcp1 | Component of P-bodies; subunit of the de-capping enzyme complex | Nonsense suppressor76 |
| ECM32 (MTT1) | Mtt1 | Upf1-like helicase | Multicopy nonsense suppressor66 |
| EFB1 (TEF5) | Efb1 | Alpha subunit of translation elongation factor eEF1B; nucleotide exchange factor for eEF1A | Antisuppressor;49 multicopy antisuppressor50,51 |
| ITT1 | Itt1 | Interacts with translation release factors eRF1 and eRF3 | Multicopy omnipotent nonsense suppressor80 |
| MBF1 (SUF13) | Mbf1 | Transcriptional co-activator | Nonsense suppressor25,37 |
| NAB2 | Nab2 | RNA-binding protein; required for nuclear mRNA export | Weak multicopy suppressor of ade1–1479 |
| NAB3 | Nab3 | RNA-binding protein required for termination of non-poly-A transcripts and efficient splicing | Weak multicopy suppressor of ade1–1479 |
| NAM7 (SUP113, UPF1, MOF4, IFS2) | Nam7 | ATP-dependent RNA helicase; component of nonsense mediated mRNA decay pathway | Recessive omnipotent nonsense suppressor58-63 |
| NMD2 (SUP111, UPF2, IFS1) | Nmd2 | Component of the nonsense-mediated mRNA decay pathway; involved in telomere maintenance | Weak recessive omnipotent nonsense suppressor58-61,57 |
| PAB1 | Pab1 | Poly-A binding protein involved in translation and polyA tail length control | Multicopy antisuppressor67 |
| PPQ1 | Ppq1 | Serine/threonine PP1 family phosphatase | Allosuppressor81,82 |
| PPZ1 | Ppz1 | Serine/threonine protein phosphatase Z | Nonsense suppressor;84 multicopy antisuppressor85 |
| PPZ2 | Ppz2 | Serine/threonine protein phosphatase Z, isoform of Ppz1p | Allosuppressor86 |
| PRE3 (CRL21) | Pre3 | Beta 1 subunit of the 20S proteasome | Nonsense suppressor hypersensitive to hygromycin B87-89 |
| RPS2 (SUP44; SUP138) | Rps2 | Protein of the small (40S) ribosomal subunit | Dominant omnipotent nonsense suppressor33,150 |
| RPS28A and RPS28B | Rps28 | Protein component of the small (40S) ribosomal subunit | Nonsense suppressor and antisuppressor35,36 |
| RPS3 (SUF14) | Rps3 | Protein component of the small (40S) ribosomal subunit | Nonsense suppressor25,37 |
| RPS9B (SUP46) | Rps9b | Protein of the small (40S) ribosomal subunit | Dominant omnipotent nonsense suppressor34,31 |
| RPT6 (CRL3) | Rpt6 | ATPase of the 19S regulatory particle of the 26S proteasome | Nonsense suppressor hypersensitive to hygromycin B87-89 |
| SFP1 | Sfp1 | Transcription factor | Weak allosuppresoor;93 antisuppressor when in the [ISP+] prion form92 |
| SIS2 (HAL3) | Sis2 | Negative regulatory subunit of protein phosphotaze Z | Antisuppressor and multicopy allosuppressor85 |
| SSA1 | Ssa1 | Heat-inducible Hsp70 chaperone | Increases nonsense readthrough in [PSI+] cells when overexpressed152 |
| SSB1, SSB2 | Ssb | Ribosome-associated Hsp70 chaperone | Multicopy antisuppressor (SSB1);50 double deletion allosuppressor for [PSI+]151 |
| SSO1 | Sso1 | Plasma membrane t-SNARE; involved in fusion of secretory vesicles at the plasma membrane and in vesicle fusion during sporulation | Multicopy suppressor100 |
| STU2 | Stu2 | Microtubule-associated protein; spindle body component controlling microtubule dynamics | Multicopy suppressor100 |
| SUP35 (s2, SUP2, SUP36, SAL3, SUF12, SUPP) | Sup35 | eRF3 translational release factor | Recessive omnipotent nonsense suppressor and allosuppressor20,13,23-26 |
| SUP45 (s1, SUP1, SUP47, SAL4, SUPQ) | Sup45 | eRF1 translational release factor | Recessive omnipotent nonsense suppressor, allosuppressor20,13,23,24,26 |
| TEF2 | Tef2 | Translation elongation factor eEF1A | Omnipotent nonsense suppressor46,47 |
| TPA1 | Tpa1 | Poly-A binding protein involved in polyA tail length control | Nonsense suppressor73 |
| UPF3 (SUP112) | Upf3 | Component of the nonsense-mediated mRNA decay pathway; involved in telomere maintenance | Weak recessive omnipotent nonsense suppressor58-60,57 |
| VTS1 | Vts1 | RNA-binding protein; stimulates deadenylation-dependent mRNA degradation | Weak omnipotent multicopy nonsense suppressor77 |
| YEF3 (TEF3) | Yef3 | Gamma subunit of translational elongation factor eEF1B; nucleotide exchange factor for eEF1A | Multicopy antisuppressor51 |
| snR18 (SNR18) | — | snoRNA U18 | Multicopy antisuppressor50 |
| 18S rRNA (RDN18–1 and RDN18–2) | — | 18S rRNA | Nonsense suppressor and antisuppressor38-41 |
| 25S rRNA (RDN25–1 and RDN25–2) | — | 25S rRNA | Nonsense suppressor42 |
| 5S rRNA | — | 5S rRNA | Nonsense suppressor and antisuppressor45 |
Note: *Alternative names are shown in the brackets; **See “Saccharomyces Genome Database” (http://www.yeastgenome.org/) and references therein for the functional role of gene products; ***Unless otherwise stated the phenotypes are caused by mutations or gene disruptions.