Figure 7. LARP4 gene-deleted knockout (KO) cells exhibit decreased 3' PAT length and stability of ribosome protein mRNAs.

(a) Western blot of LARP4 from independent isolates of WT and LARP4 KO MEFs. (b) Northern blot from 4 MEF cell lines in a; probes as indicated to the left of the panels, Rps28, Rpl32, PPP1R14A, histone H2A mRNAs, and EtBr stained gel. Densitometric lane tracings for each lane of a Rps28 exposure is shown to the right as indicated. (c) RNase H assay in presence or absence of oligo(dT) as indicated. (d e,) Time course of mRNA decay in LARP4 KO and WT MEFs after transcription shut-off (in hrs) by actinomycin-D, probed for Rps28, Rpl32 and histone H2A mRNAs as indicated to the left; e contains the same RNA preparation as in d but run on a separate gel. (f) Northern blot of 12 hr act-D time courses for LARP4 KO and WT MEFs probed for the RNAs indicated to the left. (g) Graphs showing quantifications of duplicate experiments including panels in f, as indicated. The mRNA quantification at each time was normalized against 18S rRNA in the same lane. Error bars at each time point reflect the spread of the duplicates.