Fig. 5

a Mutation of the C element leads to higher env amounts. Expression was determined by qRTPCR, calculated as ratio of spliced transcripts divided by all transcripts in env [env spliced]/[LTR transcripts] and normalized on pHSRV13. Bars represent the mean of three independent samples and error bars the standard deviation. Locations of the primers are depicted above the panels. b The C element increases SA2 strength. The usage of primer 5463 excludes amplification of SAIII splice transcripts, while other transcripts, such as genomic and pol, are excluded by the extension time. Bars represent the mean of three independent sample RNAs and error bars represent the standard deviation. c The modification of the C element leads to almost exclusive SA3 usage. The primer 42 spans the MSD-SAIII splice site junction and ensures selective amplification of SAIII spliced transcripts. Bars represent the mean of three independent samples and error bars the standard deviation