What is Gene Expression Regulation?

Question

can you explain what it is in details (WITHOUT USING WIKIPEDIA), can you tel me your source, can you include the following in your explanation : transcription factor, cellular communications, promoter, and enhancers.

Answer 1

This means how you can turn off and turn on a gene, and what are the mechanisms to do it. It basically means control of transcription in the language of molecular biology.

Answer 2

Gene regulation is the process by which your cells turn on and off genes.  While all your cells have the same DNA, what makes your cells do different things is which genes are on in each cell.  Your skin cells don't make digestive enzymes because those genes are turned off.

Promoters are the regions of DNA right before a gene that act as a signal to the enzyme that transcribes the gene telling it to get ready.  It is the region where RNA Polymerase (the enzyme that actually transcribes the gene for protein synthesis) binds on.

Transcription factors are usually proteins that either help RNA Polymerase bind or block it.  They are molecules that increase or decrease transcription rates.

Enhancers are regions of DNA, usually upstream of a gene but not always, that can work in conjunction with transcription factors to promote RNA Polymerase binding, therefore increasing transcription rates.

Answer 3

Summarised here but see links for details - http://www.ncbi.nlm.nih.gov/books/bv.fcg...

http://www.emunix.emich.edu/~rwinning/ge...

Regulation of gene expression (or gene regulation) refers to the cellular control of the amount and timing of changes to the appearance of the functional product of a gene.

Regulation can occur at different levels:-

DNA modification - eg. methylation, phosphorylation and acetylation of bases in DNA.

Transcription - eg.repressors and activators

Post-transcriptional modification - eg. splicing

RNA transport

Translation

mRNA degradation

Post-translational modifications

Answer 4

Regulation of gene expression (or gene regulation) refers to the cellular control of the amount and timing of changes to the appearance of the functional product of a gene. Although a functional gene product may be an RNA or a protein, the majority of known mechanisms regulate protein coding genes. Any step of the gene's expression may be modulated, from DNA-RNA transcription to the post-translational modification of a protein.

Gene regulation is essential for viruses, prokaryotes and eukaryotes as it increases the versatility and adaptability of an organism by allowing the cell to express protein when needed. The first example of gene regulation system was the lac operon, discovered by Jacques Monod, in which protein involved in lactose metabolism are expressed by E.coli only in the presence of lactose and absence of glucose.

Furthermore, gene regulation allows the presence in a multicellular organism of different cells types arranged in a complex pattern, hence different transcriptomes despite them having all the same genome and the generation of patterns by cellular differentiation and morphogenesis.

Answer 5

Cells have to act in a coordinated way in an organ or in a body system such as the immune system. Some cells talk to each other using soluble molecules that move through the bodies circulation. One class are cytokines that let immune cells communicate. These cytokine molecules act by binding a receptor on the target cells surface. This means one cytokine can bind many types of cells so long as they display the proper receptor on their surface. Further the reaction triggered by the cytokines binding is specific to the receiving cells type. This is how one cytokine can coordinate several cell types to begin doing the special job.

The receptor bound cytokine signals the cell, using an internal a second messenger system, to alter itself. This can be either an up or down regulation of genes that are functional in that cell type. {Genes are permanently modified in differentiated cells to eliminate them from that cell's repertoire of possible activities. This is not a reversible regulation to commit a cell to a specific tissue lineage and cell function.}

The signal messenger reaches the target cells nucleus and initiates the regulation. This involves proteins (transcription factors) binding the noncoding regulatory DNA sequences such as the gene's promoter,  where DNA polymerase begins working, and the enhancer that speeds up the transcription rate of the DNA polymerase.

http://www.jbc.org/cgi/content/abstract/...

http://tfiib.med.harvard.edu/transcripti...

http://www.gene-regulation.com/pub/datab...

Cell communication

http://kentsimmons.uwinnipeg.ca/cm1504/c...

http://www.mansfield.ohio-state.edu/~sab...

Cytokine signaling

http://131.111.189.8/~immuno/part1/lec09...

http://www.thedoctorsdoctor.com/labtests...

http://www.nature.com/nrd/journal/v3/n2/...

http://www.fasebj.org/cgi/content/meetin...