Decay of AB1157 R391 orfs90/91 and orf43 mRNA levels after exposure to 40 J.m-2UV irradiation. All results were normalised using the endogenous constitutively expressed proC gene. Standard deviation is denoted by markers above and below all data points. orfs90/91 specific mRNA levels were up-regulated immediately post exposure to UV irradiation but quickly decayed. orf43 specific mRNA levels were maximally up-regulated 7 minutes post exposure and elevated levels were sustained for over 30 minutes post exposure.