title: Introducing Dunaliella LIP promoter containing light-inducible motifs improves transgenic expression in Chlamydomonas reinhardtii.
abstract: Promoter of the light-inducible protein gene (LIP) of Dunaliella was recently isolated in our laboratory. The aim of this work is to find the light-inducible motif in the Dunaliella LIP promoter and verify its regulatory motif with a Gaussia luciferase reporter gene transformed in Chlamydomonas reinhardtii. 400 bp upstream to the translational start site of the Dunaliella LIP gene was gradually truncated and analyzed for the luciferase expression. Furthermore, this promoter comprising duplicated or triplicated light-responsive motifs was tested for its augmentation of light response. Two putative light-responsive motifs, GT-1 binding motif and sequences over-represented in light-repressed promoters (SORLIP) located in the 200 bp LIP promoter fragment were analyzed for their light responsibility. It is turned out that SORLIP was responsible for the light-inducible activity. With the copy number of SORLIP up to three showed stronger high light response compared with the native LIP promoter fragment. Therefore, we found a light-responsive DNA motif operating in Chlamydomonas and confirm a synthetic promoter including this motif displayed light inducibility in heterologously transformed green algae for the first time. This light-inducible expression system will be applied to various area of algal research including algal biotechnology.
authors.affiliation: Department of Life Science and Research Institute for Natural Sciences, Hanyang University, Seoul, Korea.
authors.forename: Kwangryul
authors.initials: K
authors.lastname: Baek
authors.affiliation: Department of Life Science and Research Institute for Natural Sciences, Hanyang University, Seoul, Korea.
authors.forename: Yew
authors.initials: Y
authors.lastname: Lee
authors.affiliation: Department of Life Science and Research Institute for Natural Sciences, Hanyang University, Seoul, Korea.
authors.forename: Onyou
authors.initials: O
authors.lastname: Nam
authors.affiliation: Department of Life Science and Research Institute for Natural Sciences, Hanyang University, Seoul, Korea.
authors.forename: Seunghye
authors.initials: S
authors.lastname: Park
authors.affiliation: Department of Chemical and Biological Engineering, Korea University, Seoul, Korea.
authors.forename: Sang Jun
authors.initials: SJ
authors.lastname: Sim
authors.affiliation: Department of Life Science and Research Institute for Natural Sciences, Hanyang University, Seoul, Korea. esjin@hanyang.ac.kr.
authors.forename: EonSeon
authors.initials: E
authors.lastname: Jin
mesh_terms: D020418:Algal Proteins / Q000235:genetics*; D016825:Chlamydomonas reinhardtii / Q000235:genetics*; D000460:Chlorophyta / Q000235:genetics*; D017930:Genes, Reporter; D008027:Light; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic; D019076:Transgenes
chemical_list: D020418:Algal Proteins; D008156:Luciferases
keywords: Chlamydomonas transformation; Dunaliella LIP promoter; GT-1 binding motif; Light-inducible motif; Sequence over-represented in light-induced promoter (SORLIP)