Was: Is the F plasmid a viroid?(Our origins)

dallas at mcvax4.d48.lilly.com dallas at mcvax4.d48.lilly.com
Fri Dec 3 10:39:55 EST 1993


In article <1993Dec3.084329.43335 at urz.unibas.ch>, bickle at urz.unibas.ch writes:
> In article <robison1.754892347 at husc10>, robison1 at husc10.harvard.edu (Keith Robison) writes:
>> 
>> What is known to be on F?  Anything other than conjugation functions?
> ^^^^^^^^^^^^^^^^^^^^^^^^^^


> Among other things, transposable elements and a set of killer genes. One of
> these codes a toxin, the other an inhibitor of the toxin. As the inhibitor
> is intrinsically unstable, cells that lose the plasmid die.
> -- 
> Tom Bickle
> Microbiology Dept, Biozentrum, Basel University
> Klingelbergstrasse 70, CH-4056 Basel, Switzerland
> + 41 61 267 21 20       bickle at urz.unibas.ch

Oh???  Lord, I've been away from E. coli genetics for a long time, but this is 
totally new to me.

Since when did 'curing' a cell of the F factor kill the cell?

Showing my age... before there was 'cloning' and recombinant DNA, some of us
studied episomes and(later) plasmids which were really in vogue in the late
sixties and early seventies.

Volumes have been published on F, F-primes, and Hfr's.  Francoise Jacob and
Jacques Monod (name dropper :-) ) launch the age of molecular biology and
genetics using E.coli and transfer genetics to describe the 'operon' certainly
with help from the lactose operon (the remnant being lacZ).  Yes many others
were involved, but I'm showing my bias.

Pick up a good textbook on Genetics from the mid-70's and enjoy!!!!! Or
reminisce.

Jim Miller
Indianapolis, IN



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