TABLE 4.
Relative abilities of rpl3 mutants to translate uncapped poly(A)− mRNAsa
| Strain | Killer | β-Galactosidase activity
|
(Pol I)/(Pol II)b | Fold WTc | |
|---|---|---|---|---|---|
| RDN1-lacZ | PGK1-lacZ | ||||
| JD1090 | K+ | 181 ± 8 | 3,875 ± 116 | 4.7 | 1.0 |
| JD1123 (xrn1/ski1) | K++ | 85 ± 6 | 1,778 ± 77 | 4.8 | 1.0 |
| JD2 (ski2) | K++ | 31 ± 1 | 122 ± 5 | 25.4 | 5.4 |
| JD19 (ski3) | K++ | 1,328 ± 74 | 2,793 ± 32 | 47.5 | 10.1 |
| rpl3 allele (in JD1090) | |||||
| L17S | K++ | 332 ± 12 | 2,240 ± 85 | 14.8 | 3.2 |
| T54A | K++ | 161 ± 5 | 1,792 ± 85 | 8.9 | 1.9 |
| T344S | K++ | 116 ± 3 | 1,592 ± 72 | 7.3 | 1.6 |
| F365Y | K++ | 179 ± 6 | 1,774 ± 67 | 10.1 | 2.1 |
| K369S | K++ | 223 ± 4 | 1,929 ± 65 | 11.6 | 2.5 |
| K384T | K++ | 130 ± 8 | 1,770 ± 64 | 7.3 | 1.6 |
Cells were transformed with lacZ reporter plasmids in which transcription was driven from either RNA polymerase I (RDN1-lacZ) or RNA polymerase II (PGK1-lacZ) promoters. The RDN1-lacZ mRNA product is uncapped and does not contain a poly(A) tail, while the PGK1-lacZ mRNA has both 7mGppp caps and poly(A) tails. β-Galactosidase activities were normalized for total protein, experiments were repeated in triplicate on three separate occasions, and means and standard deviations were calculated.
Ratios obtained by dividing the β-galactosidase activities generated from the RDN1-lacZ reporter by those generated from the PGK1-lacZ reporter were multiplied by 100%.
(Pol I)/(Pol II) ratio of mutant divided by the wild-type ratio.