A Novel Negative Fe-Deficiency-Responsive Element and a TGGCA-Type-Like FeRE Control the Expression of FTR1 in Chlamydomonas reinhardtii
Figure 2
5 and 3 deletion analysis of the FTR1 −355/−162 promoter region. A series of 5 and 3 deletions from nucleotide −355 to −162 of the FTR1 promoter region were amplified by PCR and fused to the Ars reporter gene in pJD100 and cotransformed into the arginine requiring C. reinhardtii strain CC425 with pArg7.8. Arginine independent colonies were transferred to +/− Fe TAP plates and sprayed with 10 mM XSO4 to visualize arylsulfatase activity. The fraction of arylsulfatase expressing colonies among the arginine independent colonies is indicated as Ars+/Arg+, and +Fe and −Fe indicate growth on +/− Fe TAP plates, and (+) and (−) indicate expression of the arylsulfatase gene. TubB2 stands for a minimal promoter element from the Chlamydomonas ß2-tubulin gene [42]. The cotransformation frequency was tested by PCR from 16 random selected Arg independent transformants.
