Nutritional regulation of gene expression

Summary The human genome has now been mapped with a complete sequence to follow shortly. The race is on to apply the vast amount of information contained in the billions of base-pairs. Concurrently, there is an increased demand from the public for perceived natural products. The nutritional supplement and pharmaceutical industries are broadening their product lines to meet this ever-increasing demand. As the genetic basis of disease becomes more evident, it is clear that the two industries will be forced to turn their attention to nutrients affecting gene expression. Such nutritional regulators of gene expression, or genomeceuticals (Brudnak, 2001), have enormous potential for therapeutic and prophylactic applications in both industries by affecting the integrity and expression of genes. However, there are caveats to this application, which if unheeded, may have disastrous results. This paper explores the idea behind the burgeoning area of genomeceuticals as well as some potential pit-falls that this novel area harbors. Representative examples are presented with a subsequent discussion focusing on the specifics of the application. Calculations based on: mw of GlcNAc · HCl=215.64, mw GlcNAc=179.18. Given: an infusion rate of 15 μM/Kg/min, 15 μM of GlcNAc=2.68 mg, and GHCl (glucosamine hydrochloride) is 83% GlcNAc.     

Temporal regulation of gene expression

Molecular biology gives a static--not a dynamic--vision of the mechanisms regulating gene expression. Genetics already gave to time a limited place in the explanation of living phenomena. Such a static vision is supported by the techniques--such as X-ray crystallography--used by the biologists. However time is an important parameter in the control of gene expression during the cellular response to external signals, during life and aging of organisms or even in the succession of living forms which takes place in evolution. Models are slowly moving, due to the eruption of new technologies giving access to the fast events which occur inside living cells. A new dynamic vision is progressively replacing the old one. The consequences of these changes on the form of the future biology remain still unknown.     

Translational regulation of gene expression

A report on the Cold Spring Harbor Laboratory meeting 'Translational Control', Cold Spring Harbor, USA, 7-12 September 2004.     

Hormonal regulation of gene expression

The involvement of plant hormones in the regulation of gene expression is well-recognized. Current research using molecular approaches has resulted in the isolation and characterization of a number of hormone-responsive genes and cDNAs. These genes are proving to be valuable molecular probes to study the mode of action of plant hormones. This review will briefly describe some recent molecular data from selected hormone-responsive plant systems. Results of these studies indicate potential complexity in the regulation of these genes. These results and future challenges are discussed.     

Plasmid-encoded regulation of colicin E1 gene expression.

A plasmid-encoded factor that regulates the expression of the colicin E1 gene was found in molecular cloning experiments. The 2,294-base-pair AvaII fragment of the colicin E1 plasmid (ColE1) carrying the colicin E1 structural gene and the promoter-operator region had the same information with respect to the repressibility and inducibility of colicin E1 synthesis as the original ColE1 plasmid. An operon fusion was constructed between the 204-bp fragment containing the colicin E1 promoter-operator and xylE, the structural gene for catechol 2,3-dioxygenase encoded on the TOL plasmid of Pseudomonas putida. The synthesis of the dioxygenase from the resulting plasmid occurred in recA+, but not in recA- cells and was derepressed in the recA lexA(Def) double mutant. These results indicate that the ColE1 plasmid has no repressor gene for colicin E1 synthesis and that the lexA protein functions as a repressor. Colicin E1 gene expression was adenosine 3',5'-phosphate (cAMP) dependent. Upon the removal of two PvuII fragments (2,000 bp in length) from the ColE1 plasmid, the induced synthesis of colicin E1 occurred in the adenylate-cyclase mutant even without cAMP. The 3,100-bp Tth111I fragment of the ColE1 plasmid cloned on pACYC177 restored the cAMP dependency of the deleted ColE1 plasmid. Since the deleted fragments correspond to the mobility region of ColE1, the cAMP dependency of the gene expression should be somehow related to the plasmid mobilization function.     

非编码RNA与基因表达调控

近年来,随着对基因组的深入研究,发现真核生物中存在许多形态和功能各异的非编码RNA分子,这类RNA分子并不表达蛋白质,但它们在基因转录水平、转录后水平及翻译水平起了重要的调控作用。具有调控作用的RNA分子种类非常丰富,如长链非编码RNA(long non-coding RNA,lncRNA)、miRNA、PIWI相互作用RNA(PIWI-interacting RNA,piRNA)、内源性小干扰RNA(endogenous small interfering RNA,endo-siRNA)、竞争性内源RNA(competitive endogenous RNA,ceRNA)等,它们使基因表达过程更为丰富、严谨和有序。本文综述几类典型的非编码RNA对基因表达的调节作用,以助于理解细胞中RNA分子调节网络的功能和机制。