Figure 2.

Northern blot analysis of cys-16⁺ expression. (Left panel) Northern analysis of poly (A)⁺ mRNA from wild-type N. crassa grown under low sulfur (or derepressing) (lane 1) and high sulfur (or repressing conditions) (lane 2). Northern blots were prepared probed with ³²P-labeled cys-16⁺ DNA (designated γ within figure) and am⁺ DNA (which served as a control to ensure comparability between samples). Note high level of cys-16⁺expression under low sulfur conditions. (Right panel) Northern analysis of poly (A)⁺ mRNA isolated from the Δcys-3 (18–4) strain of N. crassa grown under low sulfur (or derepressing) (lane 3) or high sulfur (or repressing) (lane 4) conditions. Blots were probed as above. Note low level expression of cys-16⁺ for both low and high sulfur levels.