Previous Article | Next Article ![]()
Mol. Cell. Biol., 12 1995, 6601-6612, Vol 15, No. 12
YL Chang, BO King, M O'Connor, A Mazo and DH Huang
Maintenance of the "on-off" state of Drosophila homeotic genes in
Antennapedia and bithorax complexes requires activities of the trithorax
and Polycomb groups of genes. To identify cis-acting sequences for
functional reconstruction of regulation by both trithorax and Polycomb, we
examined the expression patterns of several Ubx-lacZ transgenes that carry
upstream fragments corresponding to a region of approximately 50 kb. A
14.5-kb fragment from the postbithorax/bithoraxoid region of Ultrabithorax
exhibited proper regulation by both trithorax and Polycomb in the embryonic
central nervous system. Using a Drosophila haploid cell line for transient
expression, we found that trithorax or Polycomb can function independently
through this upstream fragment to activate or repress the Ultrabithorax
promoter, respectively. Studies of deletion mutants of trithorax and
Polycomb demonstrated that trithorax-dependent activation requires the
central zinc-binding domain, while Polycomb-dependent repression requires
the intact chromodomain. In addition, trithorax- dependent activity can be
abrogated by increasing the amount of Polycomb, suggesting a competitive
interaction between the products of trithorax and Polycomb. Deletion
analysis of this fragment demonstrated that a 440-bp fragment contains
response elements for both trithorax and Polycomb. Furthermore, we showed
that the integrity of the proximal promoter region is essential for
trithorax-dependent activation, implicating a long-range interaction for
promoter activation.
Copyright © 1995, American Society for Microbiology
Functional reconstruction of trans regulation of the Ultrabithorax promoter by the products of two antagonistic genes, trithorax and Polycomb
Institute of Molecular Biology, Academia Sinica, Nankang, Taipei, Taiwan, Republic of China.
This article has been cited by other articles:
Copyright © 2009 by the American Society for Microbiology. For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»