Question

As researcher, you are working on a gene named UNHAPPY ENDING 1 (UNE1). You have generated transgenic plants carrying the GFP (GREEN FLUORESCENT PROTEIN) coding sequence under the control of the UNE1 promoter (UNE1::GFP). UNE1::GFP plants show GFP fluorescence in roots only. Surprisingly, transgenic plants carrying the UNE1 coding sequence fused with GFP, under the control of the same UNE1 promoter (UNE1::UNE1-GFP plants) show GFP fluorescence in flower buds. What is the purpose of using two different constructs UNE1::GFP and UNE1::UNE1-GFP? Could you hypothesise the reasons of why GFP fluorescence is observed in roots with one construct (UNE1::GFP) and in flowers with the other construct (UNE1::UNE1-GFP)?

Answer 1

Two different constructs were used to see the tissue or organ specific expression. In case of only gfp maybe the transcription factors responsible for expression of the gene were located in the roots. Also post transcriptional and translational regulation are done in the roots itselt. But in case where une1 is fused with gfp there might be some target signal peptide that is responsible for targeting these proteins in the flowers. Maybe there are transporters that bind to the une1 seq of the protein and transports it to the flowering part from the root. Also the introns present in une1 might be responsible for organ specific expression of the protein.