Targeted expression of the DNA binding domain of DRE-binding factor, a Drosophila transcription factor, attenuates DNA replication of the salivary gland and eye imaginal disc.
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 alpha 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.
Hirose
F
F
Laboratory of Cell Biology, Aichi Cancer Center Research Institute, Chikusa-ku, Nagoya, 464-8681, Japan.
Yamaguchi
M
M
Matsukage
A
A
D000818:Animals; D030801:Animals, Genetically Modified; D004261:DNA Replication; D004330:Drosophila / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D029721:Drosophila Proteins; D005123:Eye / Q000254:growth & development / Q000378:metabolism; D005124:Eye Abnormalities / Q000235:genetics; D015870:Gene Expression; D018390:Gene Targeting; D006358:Hot Temperature; D019476:Insect Proteins / Q000235:genetics* / Q000378:metabolism*; D010641:Phenotype; D012469:Salivary Glands / Q000002:abnormalities / Q000254:growth & development / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism*
C099494:Dref protein, Drosophila; D029721:Drosophila Proteins; D019476:Insect Proteins; D014157:Transcription Factors