Abstract
Marine diatoms are thought to possess a CO2-sencing mechanism, but this mechanism is yet to be elucidated in detail. Activity of the promoter region of a carbonic anhydrase gene in the marine diatom, Phaeodactylum tricornutum (Pptca1) was analyzed, 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 demopnstrated that Pptca1 was under control of cAMP. A series of manipulated construct of Pptca1 was ligated to uidA reporter gene and introduced into P. tricornutum. Activities of manipulated promoters were measured as GUS levels in lysates grown in 5% CO2 or air. As a result, a new candidate for CO2 -responseive cis-element was identified. Relationship between cis-elements and cAMP, and interaction of the cis-elements, will be discussed.
