DNA Staining LIVING Embryos

David Mathog mathog at seqvax.caltech.edu
Fri May 27 12:31:00 EST 1994


In article <dobson-260594145945 at lsa3mac35.berkeley.edu>, dobson at mendel.berkeley.edu (Steve Dobson) writes...
>Greetings,
> 
>I'm trying to characterize chromosomal behavior of very early embryos
>(1st-4th cleavage division) in an ant ("relatively" close to drosophila). 
<stuff deleted>
>
>So....I would like to know if anyone has ever successfully used DAPI,
>YOYO-1, or other DNA stain to stain living embryos.  I have been informed
>that free radicals liberated from these dyes upon UV exposure stops normal
>chromosomal maintainence.  Is this true ?  Has anyone actually tried this ?
> Any other suggestions of ways to visualize early chromosomes ?

I tried this around 1983 in Drosophila melanogaster with DAPI and some
other similar stains.  In a nutshell, if it got in and bound DNA, then they
died. Preblastoderm Drosophila are replicating their chromosomes as fast as
they possibly can, so there isn't time for much (any?) DNA repair - even a
little DNA damage is too much.  I don't recall ever seeing a stained 
nucleus make it through a single mitosis.

As I recall, DAPI (or was it Hoecsht?) works in other systems, so you might
be able to stain ants if they replicate their DNA more slowly and have
better repair.

Good luck,

David Mathog
mathog at seqvax.bio.caltech.edu
Manager, sequence analysis facility, biology division, Caltech 



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