Twin and Siamois encode homeodomain transcription factors and are expressed in the organizer

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#Id: 5087

#Unit 6. System Physiology – Plant

One of the most extensively characterized of these factors is PIF3, a basic helix-loophelix (bHLH) transcription factor that interacts with both phyA and phyB.

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#Id: 5088

#Unit 6. System Physiology – Plant

Direct regulation of gene expression by phyB transport to the nucleus.

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#Id: 5089

#Unit 6. System Physiology – Plant

phyA is rapidly degraded following its activation by light. Thus, protein degradation, in addition to phosphorylation, is emerging as a ubiquitous mechanism regulating many cellular processes, including light and hormone signaling, circadian rhythms, and flowering time.

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#Id: 5090

#Unit 6. System Physiology – Plant

Some genes encode proteins are called CONSTITUTIVE PHOTO-MORPHOGENESIS1 (COP1), DE-ETIOLATED (DET), and FUSCA (FUS).

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#Id: 5091

#Unit 6. System Physiology – Plant

These genes encode proteins of the COP1–SUPPRESSOR OF PHYA (COP1–SPA) complex, the COP9 signalosome (CSN) complex.

TLS Online TPP Program

#Id: 5092

#Unit 6. System Physiology – Plant

COP1, another negative regulator of photomorphogenesis, is a component of the E3 ubiquitin ligase complex that targets photomorphogenesis-promoting proteins for degradation such as phyA, phyB