This Article Full Text Full Text (PDF) All Versions of this Article: 17/3/822    most recent tpc.104.029165v1 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 ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via ISI Web of Science (13) Citing Articles via Google Scholar Google Scholar Articles by Kang, X. Articles by Ni, M. Search for Related Content PubMed PubMed Citation Articles by Kang, X. Articles by Ni, M. Agricola Articles by Kang, X. Articles by Ni, M.

HYPERSENSITIVE TO RED AND BLUE 1, a ZZ-Type Zinc Finger Protein, Regulates Phytochrome B–Mediated Red and Cryptochrome-Mediated Blue Light Responses

Department of Plant Biology, University of Minnesota, St. Paul, Minnesota 55108

¹ To whom correspondence should be addressed. E-mail nixxx008{at}tc.umn.edu; fax 612-625-1738.

Plant photoreceptors that regulate photomorphogenic development include red/far-red-light–absorbing phytochromes and blue/UV-A-light–absorbing cryptochromes. We have undertaken a genetic screen to identify additional components downstream of the photoreceptors in Arabidopsis thaliana. We identified a short hypocotyl mutant under red and blue light, hypersensitive to red and blue 1 (hrb1). Mutation in HRB1 also enhances the end-of-day far-red light response, inhibits leaf expansion and petiole elongation, and attenuates the expression of CAB3 and CHS. Double mutant analysis indicates that phyB is epistatic to hrb1 under red light, and cry1 cry2 is epistatic to hrb1 under blue light for both hypocotyl growth and light-regulated gene expression responses. HRB1 localizes to the nucleus and belongs to a protein family of Drought induced 19 (Di19). HRB1 and all other family members contain a ZZ-type zinc finger domain, which in other organisms is implicated in protein–protein interactions between dystrophin and calmodulin and between transcriptional adaptors and activators. HRB1 activity is also required for red and blue light–induced expression of PHYTOCHROME INTERACTING FACTOR 4 (PIF4). pif4 shows a very similar hypersensitive response as hrb1 to both red light and blue light and is epistatic to hrb1 in control of light-regulated gene expression responses. Thus, the roles of HRB1 and PIF4 together in regulating both red and blue light responses may represent points where red light signaling and blue light signaling intersect.

This article has been cited by other articles:

				E. L. Martin-Tryon and S. L. Harmer XAP5 CIRCADIAN TIMEKEEPER Coordinates Light Signals for Proper Timing of Photomorphogenesis and the Circadian Clock in Arabidopsis PLANT CELL, May 1, 2008; 20(5): 1244 - 1259. [Abstract] [Full Text] [PDF]

				M. Chatterjee, P. Sharma, and J. P. Khurana Cryptochrome 1 from Brassica napus Is Up-Regulated by Blue Light and Controls Hypocotyl/Stem Growth and Anthocyanin Accumulation Plant Physiology, May 1, 2006; 141(1): 61 - 74. [Abstract] [Full Text] [PDF]

				X. Kang and M. Ni Arabidopsis SHORT HYPOCOTYL UNDER BLUE1 Contains SPX and EXS Domains and Acts in Cryptochrome Signaling PLANT CELL, April 1, 2006; 18(4): 921 - 934. [Abstract] [Full Text] [PDF]

				M. Chen and M. Ni RED AND FAR-RED INSENSITIVE 2, a RING-Domain Zinc Finger Protein, Mediates Phytochrome-Controlled Seedling Deetiolation Responses Plant Physiology, February 1, 2006; 140(2): 457 - 465. [Abstract] [Full Text] [PDF]