TnPhoA mutagenesis question

Rafael Maldonado rafael at howard.genetics.utah.edu
Wed Aug 30 13:37:33 EST 1995


On Tue, 29 Aug 1995 cliff at molbiol.uct.ac.za wrote:
> 
> My question is - does this mean that the fda gene 
> downstream of pgk is automatically inactive (polar mutation) OR does 
> TnphoA (or Tn5 for that matter) have a known endogenous promoter in its 
> inverted repeats ie. will the fda gene be transcribed from within the 
> transposon ? 

Hello Cliff:

Normally, yes. Tn's normally create polar mutations. Some transposons 
have those out promoters, but I think Tn5 does not have any. Any
transponible elements book could give you that information.

Anyway, you may consider internal promoters, very common in some 
operons; even a promoter can be created after the insertion, combining 
sequences from the Tn and the target. Also, polar mutations depends on 
rho-dependent termination spots. So there are some situations when the 
insertions are not polar, but they are pretty infrequent.


	Rafa

___________________________________________________________________
                                             |
Rafael Maldonado                             |  La cita ha sido
room 6160 Eccles Institute of Human Genetics |  
Department of Human Genetics		     |  retirada por respeto
University of Utah			     |
Salt Lake City, Utah 84112. USA.	     |  a la propiedad 
Rafael.Maldonado at genetics.utah.edu           |
Rafael at howard.genetics.utah.edu	             |  intelectual.
Tel: 801-581-4429			     |
Fax: 801-585-3910			     |
					                  






More information about the Methods mailing list