Expression of a β-1,3-glucanase transgene (gn1) driven by the CaMV 35S promoter is silenced in the T17 homozygous tobacco transgenic line. This silencing process is post-transcriptionally regulated and subject to developmental control. We have examined this phenomenon to investigate the developmental pathways involved in suppression and reactivation of gn1 expression as well as to identify the plant tissues where these processes occur. Analysis of β-1,3-glucanase activity and gene expression have allowed us to determine that suppression of gn1 is a very efficient process reducing the steady-state gn1 mRNA level, simultaneously, in all leaves of the plant. Gene silencing occurs a few weeks after seed germination, and is maintained throughout vegetative growth and floral development. Expression of gn1 is restored in the maturing fruit some time after fertilization. In situ hybridization analyses show that expression of gn1 is restored within the developing seeds in tissues derived from meiotically divided cells. In contrast to the high level of expression found in seedlings obtained from germinated T17 homozygous seeds, the expression of gn1 is not reactivated in plantlets regenerated in vitro from leaf explants of suppressed T17 homozygous plants that is, in plant tissues obtained by mitotic division. Thus, reactivation of gn1 expression specifically occurs along the developmental programme controlling sexual reproduction and likely throughout epigenetic modifications affecting the state of gene expression during meiosis.
Plant Molecular Biology – Springer Journals
Published: Sep 29, 2004
It’s your single place to instantly
discover and read the research
that matters to you.
Enjoy affordable access to
over 18 million articles from more than
15,000 peer-reviewed journals.
All for just $49/month
Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly
Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.
All the latest content is available, no embargo periods.
“Whoa! It’s like Spotify but for academic articles.”@Phil_Robichaud