Biosynthesis transcriptional regulators

Clearly, the control of gene expression at the transcriptional level is a key regulatory mechanism controlling carotenogenesis in vivo. However, post-transcriptional regulation of carotenoid biosynthesis enzymes has been found in chromoplasts of the daffodil. The enzymes phytoene synthase (PSY) and phytoene desaturase (PDS) are inactive in the soluble fraction of the plastid, but are active when membrane-bound (Al-Babili et al, 1996 Schledz et al, 1996). The presence of inactive proteins indicates that a post-translational regulation mechanism is present and is linked to the redox state of the membrane-bound electron acceptors. In addition, substrate specificity of the P- and e-lycopene cyclases may control the proportions of the p, P and P, e carotenoids in plants (Cunningham et al, 1996). 

A number of stimuli are known to act as inducers of TNF production (Table 9.6). Bacterial LPS represents the most important inducer, and TNF mediates the pathophysiological effects of this molecule. TNF biosynthesis is regulated by both transcriptional and post-transcriptional mechanisms. Macrophages appear to express TNF-a mRNA constitutively, which is translated only... 

Studies to date have shown that increases in gene transcription rates generally precede flavonoid production. This observation, in conjunction with studies on flavonoid-related transcription factors (TFs), suggests that gene transcription is the key point for biosynthetic gene regulation, rather than translation or post-translational steps. Post-transcriptional regulation has been reported for flavonoid biosynthesis (reviewed in Ref. 14 and recently... 

Mathews, H. et al.. Activation tagging in tomato identifies a transcriptional regulator of anthocyanin biosynthesis, modification, and transport. Plant Cell, 15, 1689, 2003. 

Enzymes That Catalyze Amino Acid Biosynthesis Are Regulated at the Level of Transcription Initiation The trp Operon Is Also Regulated after the Initiation Point for Transcription Genes for Ribosomes Are Coordinately Regulated Control of rRNA and tRNA Synthesis by the rel Gene... 

Enzymes That Catalyze Amino Acid Biosynthesis Are Regulated at the Level of Transcription Initiation... 

E P Liras, JA Asturias, JF Martin. Phosphate control sequences involved in transcriptional regulation of antibiotic biosynthesis. Tibtech 8 184-189, 1990. 

Keating, D.H. Sinorhizobium meliloti SyrA mediates the transcriptional regulation of genes involved in lipopolysaccharide sulfation and exopolysaccharide biosynthesis. J Bacteriol 189... 

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