Gene regulation

[Smiley_]

How much do we need to know about this ?

regulator gene
a gene that codes for the production of a repressor protein that inhibits the action
of an operator gene, thereby preventing transcription of a structural gene

repressor protein
a protein coded for by the regulator gene that binds to an
operator gene, which inhibits transcription of a structural gene

operator
a region of DNA situated around  a promoter that interacts with a specific repressor; when bound with a repressor protein, it prevents transcription of thestructural gene  enhancers regions found in eukaryotic DNA that act as binding sites for some activator proteins

[simpak]

What you just said should suffice?

[Yacoubb]

Its probably best to also know that a gene may not be switched on/activated depending upon its function and the specialised function of the cell. For instance, the gene for eye colour would be present in a liver cell; however, it is not activated because it is useless to the functioning of the liver cells, and ultimately, the liver organ!

But the rest is good - homeotic genes is also important! These are genes that regulate embryonic development in insects and vertebrates to ensure development occurs properly. Its a regulatory gene, coding for a polypeptide that regulates others genes (as you've mentioned, repressor proteins that inhibit the transcription, thereby inhibiting expression, of a particular gene.

[Smiley_]

Its probably best to also know that a gene may not be switched on/activated depending upon its function and the specialised function of the cell. For instance, the gene for eye colour would be present in a liver cell; however, it is not activated because it is useless to the functioning of the liver cells, and ultimately, the liver organ!

But the rest is good - homeotic genes is also important! These are genes that regulate embryonic development in insects and vertebrates to ensure development occurs properly. Its a regulatory gene, coding for a polypeptide that regulates others genes (as you've mentioned, repressor proteins that inhibit the transcription, thereby inhibiting expression, of a particular gene.

thanks



is gene regulation important so that energy is not wasted when the particular characteristic is not need it can turn off??

[simpak]

Yes, that is a major reason.  Other reasons might be for instance, developmental.  The genome of your cells needs to be able to encode for any cell type.  But you don't want your heart cells expressing all of the same genes as neurons because then that cell might not be able to carry out its function correctly.  During development there are a lot of changes to gene expression (genes switched on and off) to cement a cell fate so that cells can carry out their function appropriately and become 'the right cell'.

[Yacoubb]

thanks



is gene regulation important so that energy is not wasted when the particular characteristic is not need it can turn off??
[/quote

Essentially, yes. Protein synthesis (which is essentially gene expression), is an anabolic process, where smaller sub-unit amino acids are joined by peptide bonds to synthesise a polypeptide (complex biomacromolecule). Anabolic processes are endergonic, and so, require an input of ATP energy in order to occur. By being able to switch off (or inactivate) certain genes in a cell, it is essentially inhibiting the synthesis of particular proteins, and thereby conserving energy.

[vox nihili]

thanks



is gene regulation important so that energy is not wasted when the particular characteristic is not need it can turn off??

Energy is really the big ticket in it. The other thing you don't want to waste, of course, are resources. And of course as Simpak said developmental reasons. If you gene regulation didn't occur, there would be no cell specialisation. Well there would be, it just wouldn't be particularly effective.