Restriction of P-element insertions at the Notch locus of Drosophila melanogaster.

Abstract

P elements move about the Drosophila melanogaster genome in a nonrandom fashion, preferring some chromosomal targets for insertion over others (J. C. J. Eeken 77:6042-6046, 1980). Some of this specificity may be due to recognition of a particular DNA sequence in the target DNA; derivatives of an 8-base-pair consensus sequence are occupied by these transposable elements at many different chromosomal locations (K. O'Hare and G. M. Rubin, Cell 34:25-36, 1983). An additional level of specificity of P-element insertions is described in this paper. Of 14 mutations induced in the complex locus Notch by hybrid dysgenesis, 13 involved P-element insertions at or near the transcription start site of the gene. This clustering wa$ not seen in other transposable element-induced mutations of Notch. DNA sequences homologous to the previously described consensus target for P-element insertion are not preferentially located in this region of the locus. The choice of a chromosomal site for integration appears to be based on more subtle variations in chromosome structure that are probably associated with activation or expression of the target gene.Certain classes of transposable elements in Drosophila melanogaster are mobilized at high frequency by interstrain crosses. This makes them useful for laboratory production of new Drosophila mutants. The best studied of these transposable elements is the P element, which appears to be mobilized in the germ line, but not in the soma, of offspring derived from interstrain crosses. These dysgenic crosses generally involve mating flies that have the transposable element (P strains) with flies that do not (M strains) (12).Several newly recovered mutant alleles of the X-linked gene Notch were inspected for evidence of insertional mutagenesis. Stocks NBH9, NDTv, NPI, I(J)N27-3, N30-4, l(J)N37-10, l(J)N42-2, and l(J)N574 were produced by P-M hybrid dysgenesis (12) with the P strains Harwich and Pi.

Gene disruptions using P transposable elements: an integral component of the Drosophila genome project.

“…An apparent preference for insertion near 5' ends of genes had been noted previously for several specific genes (29,30), but excep-Disrupting tions were also known. Fig.…”

Detection in situ of genomic regulatory elements in Drosophila.

“…Hence, in most cases, the P-lacZ fusion can come under the control of Drosophila expression elements without causing major disruption to the structure or expression of an adjacent essential gene. Other workers have reported a preference of P elements for genomic targets in promoter regions, and some such insertions appear to alter the level or pattern of expression of the downstream transcript without abolishing it (20,21). Thus, many P insertions near promoters and in intergenic regions may bring the P-lacZ fusion under the control of at least some of the elements regulating expression of one or more adjacent Drosophila genes without giving a lethal phenotype.…”

Interactions between enhancer of rudimentary and Notch and deltex reveal a regulatory function of enhancer of rudimentary in the Notch signaling pathway in Drosophila melanogaster

“…An earlier report analyzed 13 hybrid-dysgenesis-induced N mutations. 21 Like N nd-p , all of the mutations were P element insertions in the first exon, upstream of the start of translation. Twelve of the mutations were recessive lethals, indicative of a large reduction in N expression and one was a recessive, hypomorphic, notchoidlike mutation similar in phenotype to N nd-p .…”