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W J Gehring

Publications and source records attributed to W J Gehring.

At least 163 records · Page 9Linked to original sources
PubMed1982

Molecular cloning of the white locus region of Drosophila melanogaster using a large transposable element.

We report the molecular cloning of a chromosome segment including the white locus of Drosophila melanogaster. This region was isolated using a deficiency extending from the previously cloned heat-shock puff sequences at 87A7 to a large transposable element containing the loci white and roughest.FB-NOF, a 7.5 kb element with partial homology to a family of inverted repeat sequences (Potter et al., 1980), is found very near the deficiency breakpoint, and is followed by DNA originating from the white locus region. Sequences totalling 60 kb surrounding this initial entry point were obtained by the cloning of successively overlapping fragments from a wild-type strain. Several rearrangement breakpoints have been mapped relative to the cloned DNA; these define the limits of the white locus and further differentiate the "white proximal region", thought to function in gene regulation, from the remainder of the locus. Insertion of the dispersed repetitive element copia into the white locus is observed in strains carrying the white-apricot allele. Analysis of several white-apricot revertants suggests that copia insertion is responsible for the apricot eye color phenotype.

Journal Article↗
PubMed1981

Protein component from Drosophila larval nuclei showing sequence specificity for a short region near a major heat-shock protein gene.

Using a nitrocellulose filter binding assay we have detected a protein component in extracts prepared from the nuclei of D. melanogaster third instar larvae which shows sequence-specific binding to a short region on a cloned D. melanogaster DNA segment containing a copy of the major heat-shock protein gene. The specificity of binding was confirmed by direct visualization of the protein DNA complexes in the electron microscope. Protein blotting experiments demonstrated that three polypeptides in the extract were capable of such sequence-specific binding. The protein binding site detected in this cloned sequence lies 800-1000 bp upstream from the presumptive transcription start.

Animals↗
PubMed1980

Transfer RNA genes of Drosophila melanogaster.

Three recombinant plasmids containing randomly sheared genomic D. melanogaster tRNAs have been identified and characterized in detail. One of these, the plasmid 14C4, has a D. melanogaster (Dm) DNA segment of 18 kb, and has three tRNA2Arg and two tRNAAsN genes. The second plasmid, 38B10, has tRNAHis genes, while the third plasmid, 63H5, contains coding sequences for tRNA2Asp. The Dm DNA segments in each recombinant plasmid are derived from unique cytogenetic loci. 14C4 is from 84 F, 38B10 is from 48 F and 63H5 is from 70 A.

Animals↗
PubMed1980

Characterization of Drosophila DNA-binding protein DB-2: demonstration of its sequence-specific interaction with DNA.

A DNA-binding protein (DB-2) was isolated from unfertilized Drosophila eggs by DNA-cellulose chromatogrphy. In competition assays with DNA from other species, DB-2 preferentially binds to Drosophila DNA. This binding protein can also be isolated from pupal nuclei and comprises only a small fraction ( < 0.01%) of the total nonhistone chromosomal proteins. In order to investigate the specificity of the interaction between DB-2 and the DNA, we attempted to isolate the DNA sequences to which DB-2 binds. DB-2 was used as a probe to screen our gene bank established by inserting randomly sheared fragments of Drosophila DNA into bacterial plasmids. Groups of plasmids were tested for binding to DB-2 by a filter binding assay. The plasmids bound to the nitrocellulose filter were eluted and used for bacterial transformation. After several cycles of transformation and cloning, two plasmids, A17 and B10, were isolated that bind DB-2 specifically, as measured by filter binding and competition assays. In plasmid A17, binding of DB-2 protects two short DNA segments of approximately 13 and 30 base pairs from digestion by DNase I. By filter hybridization according to Southern, these sequences were mapped to a defined restriction fragment. Further evidence for the binding specificity was obtained by visualizing the protein-DNA complex in the electron microscope. In salivary gland giant chromosomes, A17 DNA hybridizes to a single site (95A/B) on chromosome 3.

Animals↗
PubMed1980

A new method for the purification of DNA-binding proteins with sequence specificity.

We describe a technique for a rapid and efficient isolation and purification of proteins binding to defined DNA sequences. Cloned double-stranded DNA was covalently coupled to m-aminobenzyloximethylcellulose in order to purify proteins which recognize and bind to specific sequences on the DNA. The purification of two DNA-binding proteins from Drosophila melanogaster is demonstrated using the respective cloned DNA sequences.

Animals↗
PubMed1979

Physical map of two D. melanogaster DNA segments containing sequences coding for the 70,000 dalton heat shock protein.

The isolation of the two hybrid plasmids 56H8 and 132E3, which contain D. melanogaster (Dm) DNA sequences complementary to the mRNA coding for the 70,000 dalton heat shock protein, has been reported (Schedl et al., 1978). Here we compare the sequence arrangement in the two cloned Dm DNA segments by restriction, cross-hybridization and heteroduplex analysis. The results show that the two cloned DNA segments derive from nonoverlapping regions of the Dm genome; that they contain homologous regions present once in 56H8 and twice in 132E3; and that each homologous region is composed of three distinct contiguous sequence elements, x, y and z, which together define a 3 kb common unit. While the 2.5 kb z elements show a high degree of sequence homology in all three common units, the three x and y elements display an intriguing relationship. The localization of the mRNA coding sequences within each of these common units is presented in the accompanying paper (Artavanis-Tsakonas et al., 1979).

Animals↗
PubMed1978

Two hybrid plasmids with D. melanogaster DNA sequences complementary to mRNA coding for the major heat shock protein.

The isolation and partial characterization of two cloned segments of Drosophila melanogaster DNA containing "heat shock" gene sequences is described. We have inserted sheared embryonic D. melanogaster DNA by the poly(dA-dt) connector method (Lobban and Kaiser, 1973) into the R1 restriction site of the ampicillin-resistant plasmid pSF2124 (So, Gill and Falkow, 1975). A collection of independent hybrid plasmids was screened by colony hybridization (Grunstein and Hogness, 1975) for sequences complementary to in vitro labeled polysomal poly(A)+ heat shock RNA. Two clones were identified which contain sequences complementary to a heat shock mRNA species that directs the in vitro synthesis of the 70,000 dalton heat-induced polypeptide. Both cloned segments hybridize in situ to the heat-induced puff sites located at 87A and 87C of the salivary gland polytene chromosomes.

Base Sequence↗
PubMed1977

The 5S genes of Drosophila melanogaster.

We have cloned embryonic Drosophila DNA using the poly (dA-DT) connector method (Lobban and Kaiser, 1973) and the ampicillin-resistant plasmid pSF2124 (So, Gill and Falkow, 1975) as a cloning vehicle. Two clones, containing hybrid plasmids with sequences complementary to a 5S RNA probe isolated from Drosophila tissue culture cells, were identified by the Grunstein and Hogness (1975) colony hybridization procedure. One hybrid plasmid has a Drosophila insert which is comprised solely of tandem repeats of the 5S gene plus spacer sequences. The other plasmid contains an insert which has about 20 tandem 5S repeat units plus an additional 4 kilobases of adjacent sequences. The size of the 5S repeat unit was determined by gel electrophoresis and was found to be approximately 375 base pairs. We present a restriction map of both plasmids, and a detailed map of of the5S repeat unit. The 5S repat unit shows slight length and sequence heterogeneity. We present evidence suggesting that the 5S genes in Drosophila melanogaster may be arranged in a single continuous cluster.

Base Sequence↗
PubMed1977

Deletions of two heat-activated loci in Drosophila melanogaster and their effects on heat-induced protein synthesis.

Deficiencies that delete two heat-induced puffs in Drosophila melanogaster have been isolated. Two deficiencies delete the puff arising from 87C1, and one deletes the two puffs at 87A and 87C1. Homozygotes for these deletions can be recognized by their abnormal, transparent malpighian tubules. The influence on heat-induced protein synthesis of deleting one or both of these puffs has been examined. Unexpectedly, deleting only the 87C1 puff has no apparent effect. Deleting both the 87A and 87C1 puffs eliminates synthesis of a 71,000 dalton protein. We map a coding locus for the 71,000 dalton heat-induced protein to 87A7-B3, a seven band region which also contains a heat-induced puff. The roles of the 87A and 87C1 puffs in coding for heat-induced proteins are discussed in the light of these results.

Animals↗