OPEN ACCESS ARTICLE

This Article Free via Open Access: OA OA Full Text Full Text (PDF) Supplemental Data OA All Versions of this Article: 150/2/858    most recent pp.108.130757v1 Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via CrossRef Google Scholar Articles by Pan, Y. Articles by Schuler, M. A. PubMed PubMed Citation Articles by Pan, Y. Articles by Schuler, M. A. Agricola Articles by Pan, Y. Articles by Schuler, M. A.

SYSTEMS BIOLOGY, MOLECULAR BIOLOGY, AND GENE REGULATION

Cytochrome P450 Monooxygenases as Reporters for Circadian-Regulated Pathways^{1,[C],[W],[OA]}

Department of Cell and Developmental Biology, University of Illinois, Urbana, Illinois 61801 (Y.P., M.A.S.); Department of Plant Biology and Pathology, Waksman Institute for Microbiology, Rutgers University, Piscataway, New Jersey 08854 (T.P.M.); Department of Crop Sciences, University of Illinois, Urbana, Illinois 61801 (M.E.H.); Section of Cell and Developmental Biology, University of California, La Jolla, California 92093 (S.A.K.); and Plant Biology Laboratory and Howard Hughes Medical Institute, Salk Institute for Biological Studies, La Jolla, California 92037 (J.C.)

Cytochrome P450 monooxygenases (P450s) play important roles in the synthesis of diverse secondary compounds in Arabidopsis (Arabidopsis thaliana). Comparison of four data sets analyzing seedlings harvested over a 2-d period of constant conditions after growth with varying photoperiods and thermocycles recorded a total of 98 P450 loci as circadian regulated for at least one of the four conditions. Here, we further describe the circadian-regulated pathways using, as reporters, individual P450 loci that are likely to be rate limiting in secondary metabolic pathways. Reverse transcription-polymerase chain reaction gel blot analyses have confirmed circadian regulation of P450s in phenylpropanoid, carotenoid, oxylipin, glucosinolate, and brassinosteroid biosyntheses and have shown that both P450 and non-P450 genes in the many branches of the phenylpropanoid pathway have similar circadian patterns of expression. In silico analyses of the subsets of coregulated promoters have identified overrepresented promoter elements in various biosynthetic pathway genes, including MYB and MYB4 elements that are significantly more abundant in promoters for the core and lignin sections of phenylpropanoid metabolism. Interactions with these elements important for circadian regulation do not involve the MYB transcription factor PAP1, as previously proposed, since the expression patterns of circadian-regulated P450s are the same in pap1-D mutant seedlings as in wild-type seedlings. Further analysis of circadian-regulated promoters in other biochemical pathways provides us with the opportunity to identify novel promoter motifs that might be important in P450 circadian regulation.

The author responsible for distribution of materials integral to the findings presented in this article in accordance with the policy described in the Instructions for Authors (www.plantphysiol.org) is: Mary A. Schuler (maryschu{at}uiuc.edu).

^[C] Some figures in this article are displayed in color online but in black and white in the print edition.

^[W] The online version of this article contains Web-only data.

^[OA] Open Access articles can be viewed online without a subscription.

www.plantphysiol.org/cgi/doi/10.1104/pp.108.130757

^* Corresponding author; e-mail maryschu{at}uiuc.edu.

Received October 3, 2008; accepted April 6, 2009; published April 22, 2009.