In Article <9406011921.AA22224 at mendel.Berkeley.EDU>
"williams at MENDEL.BERKELEY.EDU" says:
> Re: Thoma et al. Plant Physiology 105:35-45 (1994) and Uknes et al. Plant
> Cell 5: 159-169.
>> In the first paper the authors describe a lipid transfer protein
> promoter/GUS fusions in transgenic Arabidopsis. GUS activity appears in the
> pollen but the LTP mRNA does not. In the second paper a similar result was
> found with the PR-1a promoter in tobacco. There the authors also tested a
> second reporter gene and found no activity in tobacco, suggesting that the
> ectopic expression was caused by the GUS coding sequences.
>> I wonder how prevelant ectopic GUS expression in pollen really is? I assume
> the following to be true:
> *there is no GUS activity in pollen of untransformed plants
> *there is no GUS activity in pollen of plants transformed with
> pBI101 (poly-linker fused to GUS with nos 3')
> *most constructs introduced into plants do not promote GUS
> expression in pollen
>> I would appreciate hearing from anyone who has detected GUS expression in
> pollen and whether they looked for the endogenous gene in pollen by in situ
> hybridization. Also, has anyone looked into whether the GUS gene effect is
> transcriptional or post-transcriptional? I guess I'm confused because
> ectopic expression in pollen is not found in all transgenics (I assume),
> and most of the reports of pollen specific expression are backed up by in
> situ or northern data. Love to hear from any interested parties!
>> Mary Williams (Sussex lab)
>I haven't looked at the background GUS expression in pollen carefully, but
I have a line transformed with a promoterless-GUS construct which might
be helpful as a control in these types of studies. I have just sent
it off to the OSU stock center.
Dupont Central Research
caspart at esvax.dnet.dupont.com