Abstract
Marine diatoms possess a CO2-sensing mechanism and transcriptional control in response to changes in the ambient [CO2]. Structure and function of promoter region of a carbonic anhydrase gene in the marine diatom, Phaeodactylum tricornutum (Pptca1) was partially clarified and it has been demonstrated that the critical CO2-response sequence was located downstream 70bp relative to the transcription-start site. This core-regulatory region comprises two putative cAMP-response elements, CRE1, 2, and a putative p300-binding site and was demonstrated that Pptca1 was under control of cytosolic cAMP in a repressive manner. A series of manipulated constructs of Pptca1 was ligated to the uidA gene and introduced into P. tricornutum. GUS activities of each transformants, grown in 5% CO2 or air were measured. As a result, a new candidate of cis-element was found. In this talk, data on determination of these critical cis-elements for CO2 response and their functions will be presented and discussed.
