TnPhoA mutagenesis question

Paul N Hengen pnh at kaylor.ncifcrf.gov
Fri Sep 8 15:37:45 EST 1995


Kimberly Walker PhD (kwalker at umabnet.ab.umd.edu) wrote:

: Actually, i think Tn5 does have outward firing promoters, but I'm not 
: sure if the active promoter is in IS50 r or IS50l.  In TnphoA, the IS50r 
: is gone.  

: Kim

There is only one base pair difference between IS50R and IS50L which creates
the promoter for kanamycin resistance in IS50L. This mutation also renders the
IS50L non-functional for transposase activity, so TnphoA MUST have IS50R in
order to actively transpose.

U25548 = TnphoA
U00004 = Tn5

In GenBank Accession number U00004:

mutation        1442
                /note="A single base pair difference exists as a 'T' at
                position 1442 and a 'G' at position 4377 within the
                inverted repeat regions of IS50L and IS50R. This mutation
                renders IS50L inactive by prematurely terminating the
                transposase."

P.S. Oh, sorry about that Kim, I just saw your retraction :-)

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