Elements of transcriptional machinery are compatible among plants and mammals

In the present work, the objective has been to analyse the compatibility of plant and human transcriptional machinery. The experiments revealed that nuclear import and export are conserved among plants and mammals. Further it has been shown that transactivationof a human promoter occurs by human transcription factor NF-κBin plant cells, demonstrating that the transcriptional machinery is highly conserved in both kingdoms. Functionality was also seen for regulatory elements of NF-κBsuch as its inhibitor IκB isoform α that negatively regulated the transactivationactivity of the p50/ RelAheterodimer by interaction with NF-κBin plant cells. Nuclear export of RelAcould be demonstrated by FRAP-measurements so that RelAshows nucleo-cytoplasmic shuttling as reported for RelAin mammalian cells. The data reveals the high level of compatibility of human transcriptional elements with the plant transcriptional machinery. Thus, Arabidopsis thaliana mesophyll protoplastsmight provide a new heterologous expressionsystem for the investigation of the human NF-κBsignaling pathways. The system successfully enabled the controlled manipulation of NF-κBactivity. We suggest the plant protoplastsystem as a tool for reconstitution and analyses of mammalian pathways and for direct observation of responses to e.g. pharmaceuticals. The major advantage of the system is the absence of interference with endogenous factors that affect and crosstalk with the pathway.