Mar 22, 2011

The Valuable Antisense



The particular terminology with respect to Gene Expression is quite confusing for beginners. at least i have faced this problem during my student life.

the sense strand ( DNA)
the nonsense or antisense strand( DNA)

here antisense or nonsense strand is the active strand that participates in transcription.
whereas
the sense strand just opposite complimentary strand.


So according to this definition - The ANTI-SENSE is VALUABLE

But this makes things complicated. And it is further complicated by Using Additional terminology
coding and non- coding strand.
here again interestingly coding strand is actually not participating strand.
and it is non-coding strand that undergoes transcription.
So say anti- sense or non- coding, it points to same strand - that undergoes transcription.

what beginner in molecular biology may think that 
in DNA helix which consist of double strand, out of the these  two strands
 one strand is sense strand and the other is antisense strand.

But this is not true if we scrutinize this definition.
why?
Because-
1) in reality particular transcription occurs only in very short stretch of DNA strand with respect to full length of DNA. ( particular gene - from promoter region to terminator region)

2) since Genes are present on both the strands, same strand of DNA may become antisense for one gene and sense strand for another gene. see in fig. gene1 and gene2 carefully template strand in two genes are not the same.






So I prefer simple and unambiguous terminology and snuggest students to follow this and keep things simple.-template strand and non- template strand for a specific gene.

Template Strand- is that stretch of DNA which acts as template for transcription. (mind it, only stretch DNA from specific promoter to terminator not full length DNA)
and
Non- Template Strand- is just a H- bonded opposite complimentary stretch of the DNA strand.

So be sensible, do not heed much to nonsense things.




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This work by Dr. Sheesh is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 2.5 India License.