Transcript
Phytochrome Interacting Factors
Lin LiChory’s lab
Content
• Members and structure
• mRNA level, protein level, phenotype of PIFs and PIFs mediated light signaling pathway
• Biological functions of PIFs
Plant Cell. 2008;20(2):337 Quail Lab
Plant Cell. 2004 ;16(11):3033 Quail Lab
...
Cell. 1998 25;95(5):657
Nature. 1999 19;400(6746):781
Science. 2000 288(5467):859
PNAS. 2000 21;97(24):13419
Quail Lab
PIF3 was found using Y2H with PhyB C-term. PIF3 binds only the Pfr form, with 10 times more affinity to PhyB than to
PhyA. PIF3 binds to G-box. Phenotype show PIF3 is a positive regulator of Phy signaling.
EMBO J. 2002 21(10):2441 Quail lab
Mutant srl2 is short under red light , Mutation In PIF4 which can Bind G box. It is a negative regulator.
Plant Cell. 2003 15(10):2399Choi Lab Plant Cell. 2004;16(6):1433 Nagy LabPNAS. 2004 16;101(46):16091 Quail Lab
New PIF3 T-DNA show short hypocotyl under R and real FL OX show long hypocotyl. PIF3 is a negative regulators of Phy signaling. PIF3 is rapidly degraded by light.
Science. 2004 305(5692):1937Quail Lab
Indentification of the Phy binding motif (APB motif). Base on the sequence homology, PIF5 and PIF6 are identified.
Based on the premise that closely related proteins may have similar functions, a new bHLH family member PIF1 is identified
investigate members of the Arabidopsis bHLH subfamily 15 for possible involvement inphy signaling, characterized bHLH072 as PIF7
PIF family members
PIF7 At5g61270 bHLH72 +/- R Hypocotyl elongation
Cotyledon expansion
Trends Plant Sci. 2007 Nov;12(11):514
The APB motif is both necessary and sufficient for binding to the biologically active pfr form of phyB
The Plant Cell, 2004 Vol. 16, 3033
ELxxxxGQ
PIF7
Physical interactions of PIFs with phy and with other PIFs
Modify from Trends Plant Sci. 2007 Nov;12(11):514
PIF7
CACGTG
E-box: CANNTG
The Plant Cell, 2004 Vol. 16, 3033
PIF7 7 7
74
G-BOX
7 7
PIF4, PIF5 and PIF7 are light induced genes
PIF6
PIF1
PIF5
Plant Cell Physiol. 44(6): 619–629 (2003)
Plant Cell. 2008 ;20(2):33
Most PIFs are degraded in light condition except PIF7PIF1
PIF4 PIF5
PIF3
PIF7
All PIFs null lines show shorter hypocotyle and OX lines show taller hypocotyl phenotype
PIF1 PIF4 and PIF5PIF3
PIF7
Model of PIF function in phytochrome signaling pathways
Nature review 2007 Vol 8;217
Biological functions of PIF1
The Plant Cell, 2007 Vol. 19: 1192
PIF1 is involved in light-induced seed germination, light-induced inhibition of hypocotyl elongation, negative hypocotyl gravitropism in the Dark, Chlorophyll accumulation in light.
Biological functions of PIF3
PNAS 2009 Vol (106) 18; 7655
PIF3 is involved in light-induced inhibition of hypocotyl elongation, chloroplast development, light-induced accumulation of anthocyanin.
PIF4 is involved in hypocotyl elongation
Current Biology 2009 Vol 19 No 6
Nature 2008 Vol 451, 480
The Plant Journal (2009) 60, 589
A quadruple mutant (pifq) lacking four PIFs(PIF1, 3, 4, and 5) is constitutively photomorphogenic in darkness :
these factors sustain the skotomorphogenic state
The Plant Cell, 2009 Vol. 21: 3535
PIF6 is involved in seed dormancy
PIF6 is expressed strongly during seed development, and that two splice variants exist, one full length (the a form), and a second, the b form, in which a cryptic intron containing the potential DNA binding domain is spliced out, predicted to lead to the generation of a premature stop codon. Loss of PIF6 increases primary seed dormancy, whereas overexpression of the b form, but not the a form, reduce dormancy.
PIF7 is involved in hypocotyl elongation
Plant Physiology, 2009, Vol. 151, 2046
Open questions
• Identification target genes of PIFs
• How are PIFs involved in hormone signaling
• Regulation of PIFs function
• Circadian and PIFs
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