Disease relevance of CHS

• Expression of stress-induced genes CHS and PR-5 was strongly up-regulated by stem removal, and was highest on day 4 after decapitation [1].
• In addition, the binding site of the human adenovirus major late transcription factor USF can compete for CG-1 binding to the chalcone synthase promoter [2].

High impact information on CHS

• PIF4 appears to specifically mediate SHB1 regulation of hypocotyl elongation and CHLOROPHYLL a/b BINDING PROTEIN3 or CHALCONE SYNTHASE expression under red light [3].
• Mutation in HRB1 also enhances the end-of-day far-red light response, inhibits leaf expansion and petiole elongation, and attenuates the expression of CAB3 and CHS [4].
• On the basis of these and previous findings, we propose that plasma membrane redox activity, initiated by photoreception, is coupled to the regulation of calcium release from an intracellular store, generating a calcium signal that is required to induce CHS expression [5].
• We investigated the signal transduction processes involved in the induction of chalcone synthase (CHS) and phenylalanine ammonia-lyase (PAL) gene expression by UV-B and UV-A/blue light in an Arabidopsis cell suspension culture [5].
• Only the UV-A/blue light induction of CHS expression involved the CRY1 photoreceptor [6].

Biological context of CHS

• This activation of the CHS promoter required an intact MRE and a newly identified sequence designated R response element (RREAtCHS) containing the BHLH factor consensus binding site CANNTG [7].
• The protein sequence deduced from the A. thaliana CHS DNA sequence is at least 85% homologous to the CHS sequences from P. hortense, Antirrhinum majus, and Petunia hybrida [8].
• Anthocyanin accumulation and changes in CHS and PR-5 gene expression in Arabidopsis thaliana after removal of the inflorescence stem (decapitation) [1].
• The UV-B and UV-A/blue light signaling pathways are therefore different from the phytochrome signal transduction pathway regulating CHS expression in other species [9].
• Both the UV-B and UV-A/blue phototransduction processes involve calcium, although the elevation of cytosolic calcium is insufficient on its own to stimulate CHS expression [9].

Anatomical context of CHS

• Co-localization of CHS and CHI was observed at the endoplasmic reticulum and tonoplast in these cells, and also in electron-dense regions that are, as yet, unidentified [10].
• However, localization of CHS and CHI to the ER and tonoplast did not appear to be affected, suggesting that other proteins may function in recruiting the "soluble" flavonoid enzymes to membranes [10].
• The protoplasts responded similarly to A. thaliana leaf tissue in light-dependent CHS transcript accumulation [11].

Associations of CHS with chemical compounds

• Staining of flavonoid endproducts with DPBA was consistent with expression of CHS and CHI in these seedlings [10].
• C1 and Sn, a R2R3-MYB and a BHLH factor, respectively, known to control tissue specific anthocyanin biosynthesis in Z. mays, were together able to activate the AtCHS promoter [7].
• Affinity chromatography and immunoprecipitation assays further demonstrated interactions between chalcone synthase, CHI, and flavonol 3-hydroxylase in lysates from Arabidopsis seedlings [12].
• Expression of other molecular markers such as CHS (encoding chalcone synthase), MEB5.2 [encoding a gene strongly up-regulated by ultraviolet-B (UV-B)] and PYROA [encoding a pyridoxine (Vitamin B6) biosynthesis enzyme] only showed slight differences between ecotypes [13].
• Analysis of gene expression in etiolated seedlings exposed to white light and in two putative regulatory mutants, ttg and tt8, demonstrated that the Arabidopsis F3H gene is coordinately expressed with chalcone synthase and chalcone isomerases is seedlings, whereas dihydroflavonol reductase expression is controlled by distinct regulatory mechanisms [14].

Physical interactions of CHS

• The KAP-2 protein that binds to the H-box (CCTACC) element in the bean CHS15 chalcone synthase promoter was purified, and internal peptide sequence used to design primers leading to the cloning of KAP-2 from bean (Phaseolus vulgaris) and barrel medic (Medicago truncatula) [15].

Regulatory relationships of CHS

• Two early chitin-induced genes and known pathogenesis-related genes such as NPR1, PAL, and CHS are activated in all the mutants whereas members of the ATL family and PR-1 and PDF2.1, which are markers of the salicylic acid (SA) jasmonate (JA) defense-response pathways, display differential expression between the mutants [16].
• Interactions within a network of phytochrome, cryptochrome and UV-B phototransduction pathways regulate chalcone synthase gene expression in Arabidopsis leaf tissue [17].

Other interactions of CHS

• Immunoblots revealed that NPPB also did not inhibit the accumulation of the chalcone synthase, chalcone isomerase, or flavanone-3-hydroxylase proteins [18].
• Analysis of flavanone 3-hydroxylase in Arabidopsis seedlings. Coordinate regulation with chalcone synthase and chalcone isomerase [14].
• Quantitative real-time PCR showed expression of genes involved in phenylpropanoid biosynthetic pathway, such as CHS and DFR, and AtGTP2 were altered in AtMYB24-ox lines [19].
• The hypothesis that flavonoids regulate auxin transport in vivo was tested in Arabidopsis by comparing wild-type (WT) and transparent testa (tt4) plants with a mutation in the gene encoding the first enzyme in flavonoid biosynthesis, chalcone synthase [20].
• However, the observed phenotypes were correlated with the amount of total shoot anthocyanin at low temperature and with the transcription of the flavonoid pathway genes PAL1 and CHS [21].

Analytical, diagnostic and therapeutic context of CHS

• Southern blot analysis indicated that CHS is a single-copy gene in A. thaliana [8].
• CHS expression is induced specifically by these wavelengths in the cell culture, in a manner similar to that in mature Arabidopsis leaf tissue [9].
• Subsequent to microinjection anthocyanin and chlorophyll accumulation was monitored as well as beta-glucuronidase (GUS) expression mediated by light-regulated promoters (chs, chlorophyll a/b binding protein (lhcb1) and ferredoxin NADP+ oxidoreductase (fnn) [22].
• Sequence analysis showed that one of them, NSCHSLK, displayed a high level of similarity to several anther-specific chalcone synthase-like (CHSLK) proteins and an ORF from chromosome I of Arabidopsis thaliana [23].
• To establish a genetic system for dissection of light-mediated signal transduction in plants, we analyzed the light wavelengths and promoter sequences responsible for the light-induced expression of the Arabidopsis thaliana chalcone synthase (CHS) promoter fused to the beta-glucuronidase (GUS) marker gene [24].

References