Karnage Posted October 12, 2005 Posted October 12, 2005 Hi. I do a project regarding gene expression but I do not exacly have a full, strong understanding of it. Can some people explain what gene expression is? I just need a clear easy-to -understand explanation. Thanks I greatly appreciate it.
rakuenso Posted October 12, 2005 Posted October 12, 2005 Where do you want us to start... eukaryotic or prokaryotic
Karnage Posted October 12, 2005 Author Posted October 12, 2005 Well i work with pheochromocytoma cells so i guess eukaryotic cells
rakuenso Posted October 12, 2005 Posted October 12, 2005 So you are you talking about cancerous adrenal cells eh? Normally it works like this... Gene expression is a tightly regulated mechanism that can go be maintained by many pathways. I.E. JaK-STAT, however in tumour cells many things can happen either genes responsible for inhibiting mitosis are deactivated/defective or pro-mitotic genes are activated/dysregulated there are also apoptic genes that can be disturbed, for example leading to the failure of Fas and FasL signaling. and many other possibilities Gene expression is controlled by a set of general transcription factors/proteins that mediate which corresponding genes are turned on/off. The Basal Core promoter consists of a TATA box that TBP binds to. The upstream promoter can be as far away as 200bp. While enhancers can reach tens of thousands bps upstream (maybe downstream even, anyone?). Anyways, a gene can only be expressed, thats is made into a primary mRNA transcript if the GTFs are bound to the promoter (in almost all cases, I haven't heard of any exceptions). Once the GTF is bound, the polymerases come in and do their job. Wikipedia can probably explain it better than I, since its such a broad topic.
Karnage Posted October 12, 2005 Author Posted October 12, 2005 Ok thanks for the information. I might still need clarification but I am satisfied with what I got right now. So according to your definition of gene expression, an increased gene expression would mean more produciton of a certain enzyme? I am testing the change in gene expression of NOS (nitric oxide synthase) when exposed to bifenthrin (a pyrethroid insecticide). I just need to know what increase and decrease in gene expression is. I think it correlates to the production of the enzyme but im not really sure. You think you can clarify this?
LucidDreamer Posted October 12, 2005 Posted October 12, 2005 I would look up transcription (eukaryotic) on wikipedia or google.
rakuenso Posted October 12, 2005 Posted October 12, 2005 yes can increased definition could mean more production of a certain enzyme. But its not the only possibility. It could also be that bifenthrin doesn't inhibit the gene expression, but rather inhibits the body's ability to use that enzyme. A typical sign of increased gene expression could and likely will result in an increase in the enzyme levels. You can find out by using a microarray for multiple genes or a variant of PCR for a single gene (The procedure is far too complicated for me understand, anyone else mind clarifying?)
Karnage Posted October 12, 2005 Author Posted October 12, 2005 Ok thanks for the information. The thing is, the aim of my research is to find bifenthrin's effect on nNOS expression in NGF-differentiated PC-12 cells. The reason for nerve growth factor is to neuronally differentiate the PC-12 cells and simulate a developing nervous system. I am trying to see if bifenthrin has the potential to induce neurotoxicity by observing its effect on the developing nervous system. If you are not aware, bifenthrin is a pyrethroid, a class of insecticides that are deemed to be "non-neurotoxic" to humans yet are selectively toxic to insects. This is why they now supplant the older insecticides (ie organochlorines, organophosphates, and carbamates). Remember, the older insecticides are deadly to humans and protests have been made to rid of them. Got any feedback on my project?
LucidDreamer Posted October 12, 2005 Posted October 12, 2005 I just need to know what increase and decrease in gene expression is. I think it correlates to the production of the enzyme but im not really sure. You think you can clarify this? In order for a cell to create an enzyme it must transcribe DNA into mRNA and then translate mRNA into enzymes. Increased gene expression means that more DNA, which are the genes, is transcribed into mRNA. Since these mRNA's are often used to make enzymes, increased gene expression leads to more enzymes. The confusion comes from the fact that sometimes mRNA is not transcribed into protein (enzymes) and it is used for other purposes. Furthermore, sometimes the enzymes that are made from mRNA are used to regulate (increase the activity or decrease) other enzymes. But in general, the increase of the expression of a particular gene means the increase of expression of a particular enzyme.
LucidDreamer Posted October 12, 2005 Posted October 12, 2005 Ok thanks for the information. The thing is, the aim of my research is to find bifenthrin's effect on nNOS expression in NGF-differentiated PC-12 cells. The reason for nerve growth factor is to neuronally differentiate the PC-12 cells and simulate a developing nervous system. I am trying to see if bifenthrin has the potential to induce neurotoxicity by observing its effect on the developing nervous system. If you are not aware, bifenthrin is a pyrethroid, a class of insecticides that are deemed to be "non-neurotoxic" to humans yet are selectively toxic to insects. This is why they now supplant the older insecticides (ie organochlorines, organophosphates, and carbamates). Remember, the older insecticides are deadly to humans and protests have been made to rid of them. Got any feedback on my project? You should first observe the effects of bifenthrin on individual cells, and then you should observe the effects of bifenthrin on animals (just in case you weren't already aware).
rakuenso Posted October 14, 2005 Posted October 14, 2005 it seems a bit strange though you are tackling a project of this complexity without basic knowledge of gene expression, are you working in a lab?
ecoli Posted October 14, 2005 Posted October 14, 2005 That's what I was thinking, rakuenso. The concept of gene expression should be simple, given the level of research you seem to be doing. In order to carry out your research, you have to expose bifenthrin to NGF-differentiated PC-12 cells and measure the level of gene expression... this is a common assay, you should be able to find plenty of info on it.
Karnage Posted October 14, 2005 Author Posted October 14, 2005 Well I do have a basic understanding of gene expression but I want to comprehend the entire thing so that t will help me write my paper on the project.
ecoli Posted October 14, 2005 Posted October 14, 2005 Well I do have a basic understanding of gene expression but I want to comprehend the entire thing so that t will help me write my paper on the project. Ok, gotcha. Then take a look at this. http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/T/Transcription.html If you have any specific question, maybe about you assay, then you should ask.
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