Table 2.
Composition of the purified RNase P holoenzyme and summary of functional analysis of each protein subunit
| Gene
|
Subunit type
|
Estimated size (kd)
|
Processing defect with subunit depletion
|
Reduction of RNA with subunit depletion
|
Immunoprecipitated RNA
|
Referencea
|
|||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| pre-tRNA
|
pre-rRNA
|
pre-P
|
P
|
MRP
|
pre-P
|
P
|
MRP
|
||||
| RPR1 | RNA | 120 | — | — | — | — | — | — | — | — | Lee et al. (1991) |
| POP1 | protein | 100.5 | Y | Y | Yb | Y | Y | Y | Y | Y | Lygerou et al. (1994) |
| POP4 | protein | 32.9 | Y | Y | N | Y | Y | Y | Y | Y | Chu et al. (1997) |
| RPP1 | protein | 32.2 | Y | Y | N | Y | Y | Y | Y | Y | Stolc and Altman (1997) |
| POP3 | protein | 22.6 | Y | Y | N | N | N | Y | Y | Y | Dicht and Tollervey (1997) |
| POP5 | protein | 19.6 | Y | Y | N | Y | Y | Y | Y | Y | this report |
| POP6 | protein | 18.2 | Y | Y | N | Y | Y | N | N | N | this report |
| RPR2 | protein | 16.4 | Y | N | N | Y | N | Y | Y | N | this report |
| POP7 | protein | 15.8 | Y | Y | N | Y | Y | Y | N | Y | this report |
| POP8 | protein | 15.5 | Y | N | N | Y | Y | Y | Y | Y | this report |
(Y) Yes; (N) no; (pre) precursor.
a
Information for Pop1p, Pop3p, Pop4p, and Rpp1p are derived from the references cited. The information reported for the remaining protein subunits is shown in Figs. 3 and 4.
b
A pop1 temperature-sensitive strain was examined at a nonpermissive temperature for RNA reduction. Relative to the mature RNase P RNA the precursor RNase P RNA levels declined less rapidly, and it is unclear whether this depletion is a result of the general decline of functional RNA levels under this condition.