Two bHLH transcription factors, bHLH48 and bHLH60, associate with phytochrome interacting factor 7 to regulate hypocotyl elongation in Arabidopsis

AbstractThe hypocotyls of germinating seedlings elongate in a search for light to enable autotrophic sugar production. Upon exposure to light, photoreceptors that are activated by blue and red light halt elongation by preventing the degradation of the hypocotyl-elongation inhibitor HY5 and by inhibiting the activity of the elongation-promoting transcription factors PIFs. The question of how sugar affects hypocotyl elongation and which cell types stimulate and stop that elongation remains unresolved. We found that overexpression of a sugar sensor, Arabidopsis hexokinase 1 (HXK1), in guard cells promotes hypocotyl elongation under white and blue light through PIF4. Furthermore, expression of PIF4 in guard cells is sufficient to promote hypocotyl elongation in the light, while expression of HY5 in guard cells is sufficient to inhibit the elongation of the hy5 mutant and the elongation stimulated by HXK1. HY5 exits the guard cells and inhibits hypocotyl elongation, but is degraded in the dark. We also show that the inhibition of hypocotyl elongation by guard cells’ HY5 involves auto-activation of HY5 expression in other tissues. It appears that guard cells are capable of coordinating hypocotyl elongation and that sugar and HXK1 have the opposite effect of light on hypocotyl elongation, converging at PIF4.

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1P123 DMA binding analyses of bHLH transcription factors by FRET measurements(Nucleic acid-binding proteins,Poster Presentations)

Seibutsu Butsuri ◽

10.2142/biophys.47.s54_2 ◽

2007 ◽

Vol 47 (supplement) ◽

pp. S54

Author(s):

Koji HASEGAWA ◽

Tatsushi GOTO ◽

Daisuke KITANO ◽

Mari KOTOURA ◽

Fumio TOKUNAGA ◽

...

Keyword(s):

Transcription Factors ◽

Nucleic Acid ◽

Binding Proteins ◽

Nucleic Acid Binding ◽

Nucleic Acid Binding Proteins ◽

Poster Presentations ◽

Bhlh Transcription Factors

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Reconstitution of Abscisic Acid Signaling from the Receptor to DNA via bHLH Transcription Factors

PLANT PHYSIOLOGY ◽

10.1104/pp.16.01825 ◽

2017 ◽

Vol 174 (2) ◽

pp. 815-822 ◽

Cited By ~ 16

Author(s):

Yohei Takahashi ◽

Yuta Ebisu ◽

Ken-ichiro Shimazaki

Keyword(s):

Transcription Factors ◽

Abscisic Acid ◽

Abscisic Acid Signaling ◽

Bhlh Transcription Factors

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The bHLH Transcription Factors MYC2, MYC3, and MYC4 Are Required for Jasmonate-Mediated Inhibition of Flowering in Arabidopsis

Molecular Plant ◽

10.1016/j.molp.2017.08.007 ◽

2017 ◽

Vol 10 (11) ◽

pp. 1461-1464 ◽

Cited By ~ 19

Author(s):

Houping Wang ◽

Yang Li ◽

Jinjing Pan ◽

Dengji Lou ◽

Yanru Hu ◽

...

Keyword(s):

Transcription Factors ◽

Bhlh Transcription Factors

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Multiple neural bHLHs ensure the precision of a neuronal specification event in C. elegans

Biology Open ◽

10.1242/bio.058976 ◽

2021 ◽

Author(s):

Konstantina Filippopoulou ◽

Carole Couillault ◽

Vincent Bertrand

Keyword(s):

Transcription Factors ◽

Quantitative Imaging ◽

Terminal Differentiation ◽

Cholinergic Neurons ◽

Antagonistic Effect ◽

Specific Class ◽

C Elegans ◽

Neuronal Specification ◽

Bhlh Transcription Factors ◽

Deleterious Genes

Neural bHLH transcription factors play a key role in the early steps of neuronal specification in many animals. We have previously observed that the Achaete-Scute HLH-3, the Olig HLH-16 and their binding partner the E protein HLH-2 activate the terminal differentiation program of a specific class of cholinergic neurons, AIY, in C. elegans. Here we identify a role for a fourth bHLH, the Neurogenin NGN-1, in this process, raising the question of why so many neural bHLHs are required for a single neuronal specification event. Using quantitative imaging we show that the combined action of different bHLHs is needed to activate the correct level of expression of the terminal selector transcription factors TTX-3 and CEH-10 that subsequently initiate and maintain the expression of a large battery of terminal differentiation genes. Surprisingly, the different bHLHs have an antagonistic effect on another target, the proapoptotic BH3-only factor EGL-1, normally not expressed in AIY and otherwise detrimental for its specification. We propose that the use of multiple neural bHLHs allows robust neuronal specification while, at the same time, preventing spurious activation of deleterious genes.

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Atoh8 in Development and Disease

Biology ◽

10.3390/biology11010136 ◽

2022 ◽

Vol 11 (1) ◽

pp. 136

Author(s):

Satya Srirama Karthik Divvela ◽

Darius Saberi ◽

Beate Brand-Saberi

Keyword(s):

Transcription Factors ◽

Embryonic Development ◽

Subcellular Location ◽

Transcriptional Regulators ◽

Special Group ◽

Helix Loop Helix ◽

Wide Range ◽

Disease Initiation ◽

Bhlh Transcription Factors ◽

Bhlh Proteins

Atoh8 belongs to a large superfamily of transcriptional regulators called basic helix-loop-helix (bHLH) proteins. bHLH proteins have been identified in a wide range of organisms from yeast to humans. The members of this special group of transcription factors were found to be involved not only in embryonic development but also in disease initiation and its progression. Given their importance in several fundamental processes, the translation, subcellular location and turnover of bHLH proteins is tightly regulated. Alterations in the expression of bHLH proteins have been associated with multiple diseases also in context with Atoh8 which seems to unfold its functions as both transcriptional activator and repressor. Like many other bHLH transcription factors, so far, Atoh8 has also been observed to be involved in both embryonic development and carcinogenesis where it mainly acts as tumor suppressor. This review summarizes our current understanding of Atoh8 structure, function and regulation and its complex and partially controversial involvement in development and disease.

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