Antisense strand of DNA

[Ken Howe]

> 
> > What does "antisense" means when it comes to DNA?
> 
> Originally, the sense strand was the strand of DNA that was READ in the 3'
> to 5' direction to transcribe the anti-parellel, complementary, RNA.  The
> other, complementary, strand in the DNA was the anti-sense strand.  > 

Huh?



More simply put, the sense strand of a "DNA sequence which is 
transcribed into RNA" is that strand whose sequence is identical to that 
of the RNA (with the replacement of T's to U's), and so the antisense 
strand is that strand whose sequence is complementary to that sequence.  
The antisense strand is the strand which is read during transcription.

For added confusion,

An antisense RNA is, 1) used in vitro for probing and for RPA, and 2) in 
vivo a small RNA molecule which usually has some regulatory activity on 
the expression of some gene by annealing to the (sense) transcript and is 
itself transcribed off of the same region of DNA except now off the 
"sense" strand, having sequence identity to the "antisense" sequence. 

So, you can see, that in vivo, both the sense and antisense strands can 
be transcribed.

Hope this helps.

Ken Howe