Example sentences for: light-responsive

How can you use “light-responsive” in a sentence? Here are some example sentences to help you improve your vocabulary:

  • In contrast, dark-grown seedlings undergo skotomorphogenesis (or etiolation), typified by elongated hypocotols and closed cotyledons [ 1 ] . COP1 was first identified through genetic screens as a negative regulator of light regulated development in Arabidopsis [ 2 ] . Arabidopsis cop1 mutant seedlings are constitutively photomorphogenic even when grown in the dark, and the severe cop1 mutants cause lethality in the late seedling stage, indicating that COP1 is essential for plant development [ 2 3 ] . Arabidopsis COP1 (Arabidopsis thaliana COP1, AtCOP1) is essential for the proteasome-dependent degradation of two transcription factors, HY5 and HYH [ 4 5 ] . These two homologous bZIP-type transcription factors directly interact with AtCOP1 and are capable of binding to light-responsive promoters to activate the transcription of many target genes [ 5 6 ] . Genome wide micro-array analysis shows that AtCOP1 regulates most, if not all, of the light-responsive genes under various light conditions [ 7 8 ] , substantiating the notion that AtCOP1 functions as a crucial developmental switch through targeting key transcription factors for degradation, thereby controlling the light-responsive gene expression and photomorphogenic development.

  • AtCOP1 contains three conserved structural domains: a RING finger at the amino terminus, a coiled-coil domain in the middle, and a carboxyl-terminal WD40 repeat domain [ 9 10 ] . Each of the three conserved domains has been shown to mediate protein-protein interactions [ 11 12 13 ] . The subcellular localization of AtCOP1 is regulated by light in a tissue specific manner [ 14 15 ] . The hypocotyl cell nuclei contain high levels of COP1 in the dark and reduced levels in the light, suggesting that the nucleocytoplasmic partitioning of AtCOP1 is adjusted by a light-responsive mechanism [ 14 16 ] . The activity of AtCOP1 is at least in part regulated by its subcellular localization, as the degradation of HY5 is dependent upon the nuclear accumulation of AtCOP1 in the dark [ 4 ] . AtCOP1 was demonstrated to carry a single, bipartite nuclear localization signal located between the coiled-coil domain and the WD-40 domain (amino acid 294-314) and a cytoplasmic localization signal, which was mapped to a region partially overlapping with the RING finger and the coiled-coil domain (amino acid 67-117) [ 17 ] . Strikingly, AtCOP1 protein forms characteristic nuclear speckles when transiently expressed in onion epidermal cells or stably expressed in transgenic Arabidopsis [ 6 18 ] . The functional role of these speckles is currently unknown; however, a subnuclear localization signal consisting of 58 residues (amino acid 120-177) is required for their formation [ 19 ] .


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