Jump to content

  • Log in with Facebook Log in with Twitter Log in with Windows Live Log In with Google      Sign In   
  • Create Account

Submit your paper to J Biol Methods today!
Photo
- - - - -

Polar increase and decrease


  • Please log in to reply
3 replies to this topic

#1 PandaCreamPuff

PandaCreamPuff

    Enthusiast

  • Active Members
  • PipPipPipPipPip
  • 43 posts
0
Neutral

Posted 23 June 2010 - 04:53 AM

Hi all

I was reading this paper that mentions how a mutation caused a "polar decrease" in the transcription of a certain gene. I'd like to know what polar means in this context.

Thanks

#2 HomeBrew

HomeBrew

    Veteran

  • Global Moderators
  • PipPipPipPipPipPipPipPipPipPip
  • 930 posts
16
Good

Posted 23 June 2010 - 12:43 PM

"Polar" in this context is refering to "upstream", "downstream", or "distal". So, for example, if you mutate a promoter that drives an operon, you'll have polar effects on all downstream genes, although those genes are wild-type (i.e. not mutant). The same type of distal effects can be seen if, for example, you mutate a repressor gene -- the genes which are effected by this protein will be de-repressed, although you've made no change (i.e. mutation) to them. Or, if you insetionally mutate a gene by inserting a transposon in it, and the transposon contains a transcriptional terminator, operonic genes downstream of the mutant one will be affected.

#3 PandaCreamPuff

PandaCreamPuff

    Enthusiast

  • Active Members
  • PipPipPipPipPip
  • 43 posts
0
Neutral

Posted 29 June 2010 - 09:13 AM

Thanks! That was very helpful.

So I presume the term is more often use in situations where a regulatory/promoter region blocks expression of multiple genes, because I thought if it involves only one gene, then one would not need to put the word "polar?" I understand the meaning I am just trying to specify if this term also applies to single gene expression changes.

#4 HomeBrew

HomeBrew

    Veteran

  • Global Moderators
  • PipPipPipPipPipPipPipPipPipPip
  • 930 posts
16
Good

Posted 29 June 2010 - 03:55 PM

If mutating a gene affects only that gene, then there are by definition no polar effects. If mutating the gene effects many scattered genes serving many different functions, a better term would be to say the mutation has "pleiotropic effects". "Polar effects" is used mostly to describe the effect a mutation has on nearby genes devoted to the same ultimate function, as in synthesis and assembly of a capsular polysaccharide, for example.




Home - About - Terms of Service - Privacy - Contact Us

©1999-2013 Protocol Online, All rights reserved.