Canadian Medical Guide > Biological Sciences > Genetic Processes > Gene Expression Regulation Terms and Definitions

Gene Expression Regulation

Medical Definition:	Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action at the level of transcription or translation. These processes include gene activation and genetic induction.
Guide Notes:	GEN or unspecified; prefer specifics; DF: GENE EXPRESSION REG
Also Called:	Gene Activation,Induction, Genetic
Previously Indexed:	Genes (1966-1980),Genes, Regulator (1973-1980),Transcription, Genetic (1973-1980),Translation, Genetic (1973-1980)

Gene Expression Regulation Categories.

	Dosage Compensation (Genetics) - A genetic regulatory mechanism which operates to equalize the phenotypic expression of characteristics determined by genes on the X chromosome so that they are equally expressed in the XY male and the XX female.
	Down-Regulation - A negative regulatory effect on physiological processes at the molecular, cellular, or systemic level. At the molecular level, the major regulatory sites include membrane receptors, genes (GENE EXPRESSION REGULATION), mRNAs (RNA, MESSENGER), and proteins.
	Epigenesis, Genetic - The genetic process by which the adult organism is realized via gradual increases in complexity of structure as opposed to a mere increase in size of preexisting structures. It includes those mechanisms causing the selective gene repression or derepression that restricts the possible fates of cells and eventually leads to their differentiated state.
	Epistasis, Genetic - A gene interaction whereby the expression of one gene interferes with or masks the expression of a different gene or genes. Genes whose expression interfers with or masks the effects of other genes are said to be epistatic to the effected genes. Genes whose expression is effected (blocked or masked) are hypostatic to the interfering genes.
	Gene Amplification - A selective increase in the number of copies of a gene coding for a specific protein without a proportional increase in other genes. It occurs naturally via the excision of a copy of the repeating sequence from the chromosome and its extrachromosomal replication in a plasmid, or via the production of an RNA transcript of the entire repeating sequence of ribosomal RNA followed by the reverse transcription of the molecule to produce an additional copy of the original DNA sequence. Laboratory techniques have been introduced for inducing disproportional replication by unequal crossing over, uptake of DNA from lysed cells, or generation of extrachromosomal sequences from rolling circle replication.
	Gene Expression Regulation, Archaeal - Any of the processes by which cytoplasmic or intercellular factors influence the differential control of gene action in archaea.
	Gene Expression Regulation, Bacterial - Any of the processes by which cytoplasmic or intercellular factors influence the differential control of gene action in bacteria.
	Gene Expression Regulation, Developmental - Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action during the developmental stages of an organism.
	Gene Expression Regulation, Enzymologic - Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action in enzyme synthesis.
	Gene Expression Regulation, Fungal - Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action in fungi.
	Gene Expression Regulation, Neoplastic - Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action in neoplastic tissue.
	Gene Expression Regulation, Plant - Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action in plants.
	Gene Expression Regulation, Viral - Any of the processes by which cytoplasmic factors influence the differential control of gene action in viruses.
	Gene Silencing - Interruption or suppression of the expression of a gene at transcriptional or translational levels.
	Genomic Imprinting - The variable phenotypic expression of a GENE depending on whether it is of paternal or maternal origin, which is a function of the DNA METHYLATION pattern. Imprinted regions are observed to be more methylated and less transcriptionally active. (Segen, Dictionary of Modern Medicine, 1992)
	Protein Processing, Post-Translational - Any of various enzymically catalyzed post-translational modifications of PEPTIDES or PROTEINS in the cell of origin. These modifications include carboxylation, HYDROXYLATION, ACETYLATION, PHOSPHORYLATION, METHYLATION, GLYCOSYLATION, ubiquitination, oxidation-reduction, degradation and lysis, peptide bond formation, and changes in molecular weight and electrophoretic motility.
	RNA Processing, Post-Transcriptional - Post-transcriptional biological modification of messenger, transfer, or ribosomal RNAs or their precursors. It includes cleavage, methylation, thiolation, isopentenylation, pseudouridine formation, conformational changes, and association with ribosomal protein.
	Trans-Activation (Genetics) - Increased rate of gene expression directed by either viral or cellular proteins. These regulatory factors (diffusible gene products) act in trans -- that is, act on homologous or heterologous molecules of DNA. (Cis-acting factors act only on homologous molecules.)
	Up-Regulation - A positive regulatory effect on physiological processes at the molecular, cellular, or systemic level. At the molecular level, the major regulatory sites include membrance receptors, genes (GENE EXPRESSION REGULATION), mRNAs (RNA, MESSENGER), and proteins.

Gene Expression Regulation Medical Definitions and Terms

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