Control of Gene Expression

Kistner A, Gossen M, Zimmermann F et al (1996) Doxycycline-mediated quantitative and tissue-specific control of gene expression in transgenic mice. Proc Natl Acad Sci USA 93 10933-10938... 

Vieira 1, Sonnier M, Cresteil T. 1996. Developmental expression of CYP2E1 in the human liver Hypermethylation control of gene expression during the neonatal period. Eur J Biochem 238 476-483. 

Environmental control of gene expression and stress proteins in plants... 

Vitamin A (retinol), present in carnivorous diets, and the provitamin (P-carotene), found in plants, form retinaldehyde, utilized in vision, and retinoic acid, which acts in the control of gene expression. Vitamin D is a steroid prohormone yielding the active hormone derivative calcitriol, which regulates calcium and phosphate metaboUsm. Vitamin D deficiency leads to rickets and osteomalacia. 

Goff SP (2001) Retroviridae the retrovirases and their rephcation. In Knipe DM, Howley PM (eds) Fields virology, 4th edn. Lippincott Williams and Wilkins, Philadelphia, pp 1871-1940 Grewal SI, Moazed D (2003) Heterochromatin and epigenetic control of gene expression. Science 301(5634) 798-802... 

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). 

Figure 1. Hierarchy of control of gene expression. A total of about 50,000 to 100,000 genes are necessary to encode a mammal, most of which encode housekeeping, structural component, or terminal differentiation gene products. Transcription factor genes regulate expression of the lower-level genes and are in turn controlled by other upper-level transcription factors.

DeRisi, J. L., Iyer, V. R. and Brown, P. O. (1997), Exploring the metabolic and genetic control of gene expression on a genomic scale , Science, 278, 680-686. 

In 1976, Hamish Munro proposed a model for the translational control of ferritin synthesis (Zahringer et al., 1976), which not only represents a crucial and remarkably far-sighted contribution to our understanding of cellular iron metabolism, but also in the more general context of the posttranscriptional control of gene expression. 

LSD1. A recent study identified LSD2 inhibitors that exhibited a 10-55-fold selectivity for LSD2 over LSD1, but that also potently inhibited MAO A and MAO B [109]. As specific inhibitors for individual demethylases and their isoforms are identified, it will be possible to elucidate the role that each enzyme plays in the epigenetic control of gene expression. 

Donahue, T. (2000). Genetic approaches to translation initiation in Saccharomyces cerevisiae. In Translational Control of Gene Expression (N. Sonenberg, J. W. B. Hershey, and M. B. Mathews, eds.), pp. 487—502. Cold Spring Harbor Laboratory Press, Cold Spring Harbor, New York. 

McKenna, N. and O Malley, B. Combinatorial control of gene expression by nuclear receptors and coregulators. Cell 108 465-474,2002. 

DeGroot, R. and Sassone-Corsi, P. Hormonal control of gene expression Multiplicity and versatility of cyclic adenosine 3, 5 -monophosphate-responsive nuclear regulators. Mol. Endocrinol. 8 145-153,1993. 

Activator proteins (and a few repressors) are important in eukaryotes, as they are in prokaryotes. The DNA sequences to which activator proteins bind in eiikaryotic DNA are called response elements. A few response elements are located within the promoter region (upstream promoter elements [UPE]), but most are outside the promoter and often clustered to form an enhancer region that allows control of gene expression by multiple signals (Figure 1-5-4). 

Control of gene expression through proteins like cAMP response element binding (CREB) protein (requires hours) Control of gene expression (requires hours)... 

Control of gene expression is also clearly different in the two species and this is likely to be of profound importance. Scientists have looked at which of 4000 genes in brain are turned on at the same time, a measure of connections in gene networks. Clear differences have been revealed. For example, in the cerebral cortex, 17-18% of the revealed gene network connections are unique to humans. 

RNA interference (RNAi) a mechanism for control of gene expression through the targeting of mRNA molecules by small-interfering RNAs (slRNA). 

---