How is distal enhancer defined?

Question

[p4alindromic]

How distant to a gene does an enhancer have to be to be called as distal enhancer? Is there an agreed upon distance for this? Quick search on the web did not give me a clear answer.

Thanks!

Answer 1

[Viz]

Typically a lot of papers set their own boundaries for what they want to define as a distal enhancer, especially when the distance is negligibly large, in the case of this paper:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3654767/

they defined distal enhancers with a range of 80kb - 114kb up or downstream since that is what they observed.

While this article:

https://www.nature.com/articles/ng.3884

defines distal as >1kb and proximal <1kb. It depends on the context of what you're doing but typically it's up to the discretion of the researcher once you've reached a large enough distance of around 1 - 2kb upstream.

[p4alindromic]

I think in the second paper, proximal means promoter and distal means enhancer. I am more interested in classifying an enhancer based on it being relatively close to a gene or quite distant from a gene. What would be an approximate distance threshold then?