Upstream vs downstream regulatory element

[AntonFreeman]

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Could someone explain difference between upstream vs downstream regulatory element on a gene?

 

[Pre-Med Village]

Could someone explain difference between upstream vs downstream regulatory element on a gene?

Regulatory motifs may be found within genic regions or within intergenic regions. For intergenic regions, upstream means in the direction of the 5' region of the sense strand from the genic region, meaning towards the 3' region of the antisense strand. RNA polymerase moves upstream to downstream. Most regulatory elements, such as a promoter region, are typically upstream, while others, like enhancers, may be upstream or downstream. I hope this helps.

 

[AntonFreeman]

so if there is gene A and B on same pathway,and you need gene A to be expressed first before B, is gene A located upstream of gene B?

 

[Pre-Med Village]

so if there is gene A and B on same pathway,and you need gene A to be expressed first before B, is gene A located upstream of gene B?

I think that this statement is true for prokaryotes, where several genes may share the same promoter within the structure of the bacterial operon. I think the question you are dealing with must be in the context of an operon.

For eukaryotic gene expression, though, with enhancers, silencers, differential splicing, histone acetyltransferase, bidirectional promoters and what-not, I would beware of a statement like this. Eukaryotic gene expression is a topic that grows and changes every year with research discovery.

 

[whiteshadodw]

lac operon is an example of an upstream regulatory element. the operon is on the 5' end of the gene in DNA.

Trp operon is an example of a downstream regulatory element. Trp levels control the transcription of the gene downstream. once the gene is being transcribed it can be modulated by the Trp levels:

http://en.wikipedia.org/wiki/Trp_operon