Gene Expression and Gene Regulation

Gene expression is the process by which information from a gene is used in the synthesis of a functional gene product. These products are often proteins the product is a functional RNA. The process of gene expression is used life – eukaryotes (it is called multicelluler organism), prokaryotes ( single celluler organism, bacteria) and viruses - to generate the macromolecular machinery for life. Several steps in the gene expression process may be modulated, including the transcription, RNA splicing, translation, and post-translational modification of a protein.
Gene regulation gives the cell control over structure and function, and is the basis for cellular differentiation, morphogenesis and the versatility and adaptability of any organism. Gene regulation may also serve as a substrate for evolutionary change, since control of the timing, location, and amount of gene expression can have a profound effect on the functions (actions) of the gene in a cell or in a multicellular organism.
In genetics gene expression is the most fundamental level at which genotype gives rise to the phenotype. The genetic code is "interpreted" by gene expression, and the properties of the expression products give rise to the organism's phenotype.
Transcription: Transcription occurs in three steps in both prokaryotes and eukaryotes: initiation, elongation and termination. Transcription begins when the double-stranded DNA is unwound to allow RNA polymerase binding. Once transcription is initiated, RNA polymerase is released from the DNA. Transcription is regulated at various levels by activators and repressors and also by chromatin structure in eukaryotes.
Translation: Translation or protein synthesis is a multi-step process with initiation, elongation and termination steps. The process requires macromolecules like ribosomes, transfer RNAs (tRNA), mRNA, and protein factors as well as small molecules like amino acids, ATP, GTP, and other cofactors. There are specific protein factors for each step of translation. The overall process is similar in both prokaryotes and eukaryotes, although particular differences exist.
RNA splicing: ?????

Gene Expression Technique:

1. Gene expression is the process by which information from a gene is used in the synthesis of a functional gene product. These products are often proteins (in non-protein coding genes such as rRNA genes or tRNA genes), the product is a functional RNA. The process of gene expression is used by all known life - eukaryotes (multicellular), prokaryotes (bacteria) and viruses - to generate the macromolecular machinery for life.
Several steps in the gene expression process may be modulated, including the transcription, RNA splicing, translation, and post-translational modification of a protein. Gene regulation gives the cell control over structure and function, and is the basis for cellular differentiation, morphogenesis and the versatility and adaptability of any organism. Gene regulation may also serve as a substrate for evolutionary change, since control of the timing, location, and amount of gene expression can have a profound effect on the functions (actions) of the gene in a cell or in a multicellular organism.
In genetics gene expression is the most fundamental level at which genotype gives rise to the phenotype. The genetic code is "interpreted" by gene expression, and the properties of the expression products give rise to the organism's phenotype.
Gene Expression Technique:
The expression of genes can be determined by computing mRNA levels with help of following technique like
I. microarrays,
II. cDNA sequence tag sequencing,
III. SAGE (serial analysis of gene expression) tag sequencing
IV. MPSS (massively parallel signature sequencing)
or various applications of multiplexed in-situ hybridization.
Above all of these methods are tremendously noise-prone or subject to bias in the biological measurement and a chief research field in computational biology involves developing statistical tools to segregate signal from noise in high-throughput gene expression studies.
This study is often used to determine the genes mixed up in a disorder: one might compare microarray data from cancerous epithelial cells to data from non-cancerous cells to determine the transcripts that are up-regulated and down-regulated in a particular population of cancer cells.