FIG. 4.

RT-PCR analysis of the ORF73 5′ UTR. BCBL-1 RNA or DNA was reverse transcribed with primer 7308 and PCR amplified with the primers indicated above the lanes. A one hundred-base-pair molecular size ladder is shown in the left lane of each gel. The 600-bp fragment hybridized to the polylinker sequence in the probe. Where indicated (RT−), reverse transcriptase was omitted from the reaction. An ethidium-bromide-stained gel (top) and an autoradiogram of the same gel hybridized with a probe specific for the UTR (lower gel panel) are shown. Note that in the RT+ panel two fragments are amplified in lane 7 and none in lane 9. The deduced structure of the 5′ UTR and the locations of primers (small arrows) are shown below the gels. The numbers on the right of the diagram denote the 5′ end and splice junction, as determined from RACE clones.