Fig 4.

Size homogeneity of cat mRNAs. T. vaginalis cells were cotransfected with the different pcat plasmids and the pgfp-UAAA plasmid, which was used as an internal control for transfection and transcription. An RT-PCR approach was used, and samples from 24 and 30 cycles of amplification are shown. Amplification products were electrophoresed in a 5% acrylamide gel and stained with ethidium bromide. The lower band of about 200 bp corresponds to the RT-PCR product derived from the gfp mRNA control. This band migrates at the expected size, and it is constant and well defined throughout all the assays. The upper band of about 235 bp corresponds to the RT-PCR product derived from the cat mRNAs. This band is well defined for the cases where the transfected plasmids contain the UAAA motif (parental UAAA, AAUAAA, UAAAG, and GUAAA). RT-PCR products derived from plasmids without the UAAA motif appear as ill-defined bands compared with the gfp control in each lane, thus suggesting mRNAs of heterogeneous size and low abundance (GAAA, UCAA, UACA, UAAC, and GCCC). mwm, molecular size markers.