gene identification troubles
R.D. Haigh
rxh at leicester.ac.uk
Mon Mar 2 15:03:04 EST 1998
Hi Tammy
I'll present my background first - I'm a bacteria man so some of my
info will be biased that way - I never did zoology either what sort
of bug(?) is L.littorea ?
My answers
1.I can't help you here other than to agree it seeems odd you should
be picking up RNA genes in this sort of screen.
2. The age old problem - you're enormously overjoyed that they're novel
but what the hell is it anbd no clues available. The obvious next step has
got to be trying to make knockouts - if these genes are only required for
stres responses you might expect mutants would be non-lethal in
permissive conditions, though probably showing phenotypes which might
help with working out function. This all requires knockout
strategies which may not exist for L.littorea (or you may not have
them) so the next best option is overexpress your gene product, make antibodies and
check the expression pattern either in whole organisms or cell
fractions.
By my calculations you are seeing 25-40% (?!*) of your clones are
coming up with homologs - how good are these? do any of them make any
sense ?
3. I haven't seen any (but can't say I've looked hard) - generally
everything goes into Genbank and if it doesn't, it is probably because
someone doesn't want it available so you won't find it anyway
4. Sorry not my subject
5. Protein translations are usually very useful - when looking across
species (especially in bacteria) DNA matches are usually much poorer
than protein. I tend to favour blast searches using a translation
either against the protein database or even a translated version of
the entire genbank DNA database - all available on the ncbi blast pages
Have you tried any prediction programs - you should be
able to get a fair idea of the cellular location of your protein but
do note they are not infallible - PSORT at psort.nibb.ac.jp is
very good for bacteria but i can't vouch for eukaryotes. there are also
lots of useful programs (and some crap ones - you'll have to work out
for yourself) at expasy.hcuge.ch/www/tools.html.
I hope my ramblings are some help
Richard
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Richard Haigh
Department of Microbiology and Immunology,
University of Leicester,
University Road,
Leicester. LE1 9HN UK
Phone: 0116 2523017
FAX : 0116 2525030
Email : rxh at nospam.le.ac.uk
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