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Another new blue light receptor...?

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Another new blue light receptor...?

Postby bta » Sat Jun 09, 2007 7:24 am

Hi,

Here is an abstract from a very interesting paper regarding the action spectrum (hint: it's blue) for HID and mRNA accumulation (via. Lhl4 gene) in green alga. I wonder if the receptor they are referring to is one of the known ones?

I had to copy/paste as I do not have 5 posts and can not post a link to the Oxford Journals page. After I post this I will post the link as I will have 5 posts
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Action Spectrum for Expression of the High Intensity Light-inducible Lhc-like Gene Lhl4 in the Green Alga Chlamydomonas reinhardtii

Lhl4 encodes a distant relative of light-harvesting Chl-a/b proteins in the green alga Chlamydomonas reinhardtii. Lhl4 mRNA markedly accumulated within 30 min after illumination and in proportion to the light intensity up to a fluence rate much higher than that required for photosynthesis. The high intensity light (HL)-induced accumulation of Lhl4 mRNA required continuous illumination, and the mRNA level rapidly decreased when the cells were placed in the dark. HL only slightly stabilized the mRNA, suggesting that the HL-induced expression of the Lhl4 gene is primarily regulated at the level of transcription. Blue light was more effective for inducing Lhl4 gene expression than green or red light, and far-red light had no effect. The action spectrum for Lhl4 gene expression was examined at wavelengths between 325 and 775 nm using the Okazaki Large Spectrograph. The obtained spectrum showed a distinct peak in the blue region (450 nm) and a shoulder in the UV-A region (375 nm). The curve in the spectrum rose steeply in the short wavelength UV region. In addition, we observed two minor peaks in the green (575 nm) and the red (675 nm) regions. The action spectrum suggests that a blue/UV-A light photoreceptor with a flavin-based chromophore participates in the HL response of Lhl4 gene expression. However, the hypersensitivity to near UV-B light suggests the involvement of an unidentified UV light perception system in the expression of the Lhl4 gene.

(Received October 17, 2005; Accepted January 9, 2006)
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Last edited by bta on Sat Jun 09, 2007 7:25 am, edited 1 time in total.
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Postby bta » Sat Jun 09, 2007 7:25 am

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Postby MrMistery » Sat Jun 09, 2007 10:17 am

Maybe, but we should be cautious in accepting this. The article says that the transcription of the gene is stimulated by blue and UV light, but does not say anything about the actual light-sensing protein. Furtermore, from the description of how the receptor behaves, it is very similar to a protein in the phototropin family.
Much work remains to be done in the field of blue light receptors in plants.
Regards,
Andrew
"As a biologist, I firmly believe that when you're dead, you're dead. Except for what you live behind in history. That's the only afterlife" - J. Craig Venter
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