Figure 3.

S1 protection analysis of SUA7 transcripts. Total RNA was hybridized with a single stranded template strand DNA probe containing SUA7 DNA from +24 to –454 relative to the start of translation. The hybridized region was analyzed by S1 protection as described in Materials and Methods. (A) Autoradiogram showing the protected products after separation on a sequencing gel. The size of the protected products was determined by comparison to the sequencing ladder generated with a primer containing the same 5′-end as the single stranded DNA probe. The positions for the expected short and long RNAs are marked with arrows. RNA was isolated from cells in exponential phase (lane 1), after heat shock (lanes 2 and 5), after amino acid starvation (lanes 3 and 6) and in stationary phase (lane 4). Samples from the amino acid starved cells contained 20 µg of total RNA; the other samples contained 30 µg of total RNA. Lanes 7 and 8 contain labeled probe in the presence and absence of nuclease S1, respectively. (B) A darker exposure of the protected products from the autoradiogram shown in (A).