Fig. 2.

Increase in temperature activates BES promoters. T. b. rhodesiense strain YTat 1.1, carrying either the MES or BES promoter reporter construct was grown at 28°C in Cunningham’s medium supplemented with 10% heat inactivated FBS and 2 mM L Gln. The two cultures (grown in parallel) were diluted in duplicate to 1 × 106 cells/ mL and incubated overnight at 28°C. Time point 0 hours represents the cultures at 28°C. One flask of each culture was placed at 22°C and the other at 37°C. Total RNA was prepared with Trizol reagent (Invitrogen) and Northern blotting was performed using a standard protocol. The probes used, (A) BSD, (B) HSBP1 and ESAG7/6, are indicated on the right (probe details are available upon request). The probe against ESAG7 and ESAG6 recognizes a region with high degree of identity between the two genes. Numbers in the lanes indicate the levels of the detected mRNAs from three independent experiments (± SEM) normalized relative to the HSBP1 mRNA amounts in the samples. The lowest steady-state level is set to 1. The large rRNAs were visualized by staining with methylene blue.