Determinants of heat shock-induced chromosome puffing

647

304

We generated and characterized >500 Drosophila strains that carry single copies of a novel P-element enhancer detector. In the majority of the strains, the p-galactosidase reporter gene in the P-transposon responds to nearby transcriptional regulatory sequences in the genome. A remarkable diversity of spatially and temporally regulated staining patterns is observed in embryos carrying different insertions. We selected numerous strains as markers for different embryonic organs, tissues, and cells. Many of these strains should allow the study of complex developmental processes, such as nervous system development, which have not been convenient to analyze previously. Also, we present genetic evidence that some of the detected regulatory elements control nearby Drosophila genes. In light of our results, we discuss the diversity and complexity of cis-acting regulatory elements in the genome and the general applications of the enhancer detector method for the study of Drosophila development.

Section: ^-Galactosidase Stainingmentioning

confidence: 99%

P-element-mediated enhancer detection: a versatile method to study development in Drosophila.

Bellen¹,

O’Kane²,

Wilson³

et al. 1989

647

304

“…X-gal staining of transformant lines was performed according to Simon et al (1985) except that embryos were fixed by shaking in a 1 : 4 ratio of 4% paraformaldehyde (freshly prepared in 1 x PBS) to heptane for 30 min at room temperature. Alternatively, formaldehyde stored under anoxic conditions in the absence of methanol was also used as a fixative.…”

Section: X-gal and Immunohistochemical Staining Of Embryosmentioning

confidence: 99%

A sequence-specific DNA-binding protein that activates fushi tarazu segmentation gene expression.

Ueda¹,

Sonoda²,

Brown³

et al. 1990

185

152

The Drosophila segmentation gene fushi tarazu (ftz) is expressed at the cellular blastoderm stage in a pattern of seven transverse stripes; the stripes lie out of register with the segmental primordia, spanning alternate segmental boundaries. The zebra element, a 740-bp DNA sequence upstream of the ftz translational start, directs striped expression of lacZ when introduced into the fly genome. We have purified to homogeneity a sequence-specific DNA-binding factor, FTZ-F1, that binds to two sites located within the zebra element and to two sites within the ftz protein-coding sequence. FTZ-F1 DNA-binding activity is first detected in extracts of 1.5-to 4-hr embryos, coincident with the time of ftz expression in stripes; the activity then diminishes before reappearing during late embryo, larval, and adult stages. When one of the FTZ-Fl-binding sequences in the zebra element is mutated by 2-or 4-base substitutions, the binding to FTZ-F1 is disrupted in vitro, and the intensity of lacZ expression is reduced in transformed embryos, especially in stripes 1, 2, 3, and 6. The results suggest that FTZ-F1 is a transcriptional activator necessary for the proper expression of the ftz gene.

“…When these constructs are inserted into the Drosophila germ line, yolk protein DNA is flanked upstream by -7.2 kb of rosy (ry) gene DNA and downstream by -7.3 kb of hsplacZYA DNA. The transformation vector was made by modification of the ends of a XhoI-XbaI fragment from pSPI.1 (Lis et al 1983) containing the hsp-lacZ gene and then insertion of it into the pUC13 polylinker of the transformation vector CP20.1 (Simon et al 1985). The resulting vector, pSXhLac-7 (constructed by Claude Maina), has the fusion site 5'-G/GTCGAC/ TCTAGA/GTCGAGAAATTT-3' (the SalI and XbaI sites are bounded by slash marks and the hsp70 DNA, which begins at -195, is underlined).…”

Section: Construction Of P-element Plasmidsmentioning

confidence: 99%

“…The initial yp(1 +2)M13 structure was assembled from pYP!-M13676 and pYP2-M13676 by fusion at the intergenic HindIII site . The final structure was cloned into the CP20.1 P-element transformation vector (Simon et al 1985).…”

Section: Construction Of P-element Plasmidsmentioning

confidence: 99%

Ovarian follicle cell enhancers from the Drosophila yolk protein genes: different segments of one enhancer have different cell-type specificities that interact to give normal expression.

Logan

Wensink²

1990

This paper examines ovarian transcription of the divergently oriented yolk protein genes 1 and 2 (ypl and yp2) of Drosophila melanogaster. We report germ line transformation results demonstrating that ypl and yp2 are transcribed in the same subpopulations of ovarian follicle cells. Our results show that this expression pattern is directed by two enhancers: ovarian enhancer 1, located between the genes, and ovarian enhancer 2, located within the first exon of yp2. Analysis of the expression pattern resulting from alterations in ovarian enhancer 1 demonstrates that different segments of this enhancer have different positive or negative effects on the cell-type specificity of transcription.