Chorion-deficient Mutants ?

pvalerio at pvalerio at
Sun Oct 23 20:09:32 EST 1994

In article <54796.corley at>, corley at ("Graham Corley-Smith") writes:
> RE: message of 23 Oct 94 15:44:18 -0230 from pvalerio at
>    regarding possibility of making chorion-deficient mutants.
> Hi all,
>    I find the concept of producing chorion deficient mutants intriguing.
> However, I was under the impression that the
> chorion is extremely important in fertilization for reasons most of you I
> am sure are familiar with.  For example, if the chorion was lost, would not
> also the micropyle be lost?  Therefore, losing a primary block to
> polyspermy?  Is anyone aware of experiments where the chorion has been
> removed before fertilization and viable progeny have been produced?
>     Regards,
>       Graham

Yes, a major obstacle to overcome would be to find a way of establishing a
powerful secondary polyspermy block. A recent paper on the fertilization of
mammalian eggs after zona removal describes the membrane-associated
polyspermy block, perhaps indicating that this mechanism could be 
artificially enhanced to replace the primary block (the chorion) in fishes.
The issue is not a simple one, but interesting to consider.

   The paper is :

Horvath, P.M., Kellom, T., Caulfield, J. Boldt, J. 1993.
 Mechanistic Studies of the Plasma-membrane Block to Polyspermy in
 Mouse Eggs. Molecular reproduction and Development, 34(1): 65-72.

- Paul.

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