They showed that GFP protein could be expressed in the organisms with which they can be used as a gene expression marker and protein localisation. They used GFP in transcriptional fusions to characterize the expression pattern of genes. They used the transformation techniques using DNA encoding GFP. Solution They showed that GFP protein could be expressed in the organisms with which they can be used as a gene expression marker and protein localisation. They used GFP in transcriptional fusions to characterize the expression pattern of genes. They used the transformation techniques using DNA encoding GFP..