Fig. 2. Efficient silencing of cop gene expression mediated by ‘RNAi’-like constructs. (a) DNA-constructs tested for their RNAi mediating activity. (b) Relative amounts of opsin in different pSR25 transformants compared to the wild-type as determined by densitometric measurements of the Cop-band intensity on western blots using immunodetection. (c) Comparison of purified eyespot membranes (S3-fraction) of recipient cw15 arg^-A cells and the transformant cop^d12. (d,e) Comparison of cop-transcripts by RNA-blot analysis. (d) Equal amounts of mRNA from wt (CC2454) cells and pSR25 transformant 35 (cop^d) were fractionated on an agarose gel, blotted and probed with full length DIG-labeled cop-cDNA. (e) 5 µg wt mRNA and 11 µg of transformant mRNA were hybridized with DIG-labeled cop fragment comprising exon 1-3.