Molecular and Cellular Biology, September 1999, p. 6020-6028, Vol. 19, No. 9
0270-7306/99/$04.00+0
Copyright © 1999, American Society for Microbiology. All rights reserved.
Laboratory of Cell Biology, Aichi Cancer Center Research Institute, Chikusa-ku, Nagoya, 464-8681, Japan
Received 11 January 1999/Returned for modification 22 February 1999/Accepted 26 May 1999
The promoters of Drosophila genes encoding DNA
replication-related proteins contain transcription regulatory elements
consisting of an 8-bp palindromic DNA replication-related element (DRE)
sequence (5'-TATCGATA). The specific DRE-binding factor
(DREF), a homodimer of the polypeptide with 709 amino acid residues, is
a positive trans-acting factor for transcription of
DRE-containing genes. Both DRE binding and dimer formation are
associated with residues 16 to 115 of the N-terminal region. We have
established transgenic flies expressing the full-length DREF
polypeptide or its N-terminal fragment (amino acid residues 1 to 125)
under the control of the heat shock promoter, the salivary
gland-specific promoter, or the eye imaginal disc-specific promoter.
Heat shock induction of the N-terminal fragment during embryonic,
larval, or pupal stages caused greater than 50% lethality. This
lethality was overcome by coexpression of the full-length DREF. In
salivary glands of the transgenic larvae expressing the N-terminal
fragment, this fragment formed a homodimer and a heterodimer with the
endogenous DREF. Ectopic expression of the N-terminal fragment in
salivary gland cells reduced the contents of mRNAs for the 180-kDa
subunit of DNA polymerase
and for dE2F and the extent of DNA
endoreplication. Ectopic expression of the N-terminal fragment in the
eye imaginal discs significantly reduced DNA replication in cells
at the second mitotic wave. The lines of evidence suggest that the
N-terminal fragment can impede the endogenous DREF function in a
dominant negative manner and that DREF is required for normal DNA
replication in both mitotic cell cycle and endo cycle.
This article has been cited by other articles:
| J. Bacteriol. | J. Virol. | Eukaryot. Cell |
|---|
| Microbiol. Mol. Biol. Rev. | Clin. Vaccine Immunol. | All ASM Journals |
|---|