The Mechanism Study Of Arabidopsis CIB1 And CO Regulating FT Transcription

Flowering is an important stage in the life process of plants,representing the transition of plants from vegetative growth to reproductive growth.Plant photoreceptors regulate photoperiod related genes by sensing light signals,thereby regulating flowering time.CRY2,the blue light receptor,interacts with CIB1 and CO in a blue light-dependent manner to regulate the transcription of the floral FT gene and the flowering time of plants.However,in the previous research,although the functions of CIB1 and CO optical signal transmission(both involved in the regulation of FT transcription)have been found through molecular genetics.Due to the complex optical signal transmission network in plant cells,they are more susceptible to interference by other light signal-related transcription factors(such as:GI,PIFs,CBLs,etc.).The interaction between CIB1 and CO,and how to coordinate the specific molecular mechanisms such as FT transcription have not been resolved.In order to solve the above difficulties,we reconstructed the CO-CIB1 co-transcription system in human HEK293 T cell.Because in human HEK293 T cells,it will not be affected by other plant light signal proteins.We found that CIB1 can directly interact with CO,and determined the binding region of CO and CIB1 on the FT gene.At the same time,we analyzed the molecular mechanism that CIB1 promote the combination of CO with FT-G.CIB1 and CO form protein complexes to enhance their transcriptional activity.Through research in the expression system of HEK239 T cells,this study has reached the following conclusions: 1.CIB1 and CO can directly bind to FT-C,FT-D,FT-G and FT-P in vitro and activate their transcription.2.CIB1 will promote the combination of CO and FT-G,and inhibit the combination of CO and FT-C,FT-D and FT-P.3.CIB1 and CO have the strongest ability to bind FT-G and activate its transcription.