Upstream and Downstream Regions

[gene26]

The transcriptional enhancer spans the nearby 5' gene flanking sequences from - 72 to -205 and is both necessary and sufficient for specific transcription. The region downstream of -72 contains a promoter

so -72 to -205 is on above (upstream) or below (downstream) to 5' coz it says minus (i guess its above 5' region)

again it says downstream of -72 does it mean region below 5'...??

can anyone explain about these plus (+) and minus (-) downstream, upstream regions...

[relaxin]

The position at the transcription start site is designated +1, the sequence downstream from +1 will carry a "+" sign, and will appear in mRNA. Any sequence upstream from "+1" will carry a "-" sign, this sequence often contains promter and enhancer sequences. The first base will be "-1", and the number will increase as it is farther away from the "+1". So "-72" will be closer to the "+1" site than the "-205".

The terms "upstream" and "downstream" are only relative terms. As in case you are standing in the middle of a river, upstream is the part of river where water is coming towards you, and downstream is where water is moving away from you. Depending on where you are standing, the reference of "upstream" and "downstream" can be changed.

The "5'-region" is also a nonspecific term. When you mean 5'-end of mRNA, it is the beginning of the transcript, starting from "+1".

[CrowSan]

Basically I think what that is saying that there is first an enhancer sequence (-502 to -72) then a promoter sequence between -72 and the transcription start site at +1 (so the promoter is "downstream" i.e. 3' of -72)

In general when people say "upstream" it is 5' of where you are in the DNA and "downstream" is 3' of where you are "standing".

In otherwords: "Upstream" of -72 site is an enhancer, and "downstream" of -72 site is the promoter, transcription start site and the gene.

Hope this helps (and sorry about delay in replying)