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P Spierer

Publications and source records attributed to P Spierer.

32 records · Page 2Linked to original sources
PubMed1986

The Ace locus of Drosophila melanogaster: structural gene for acetylcholinesterase with an unusual 5' leader.

The Ace locus of Drosophila melanogaster has been mapped at the molecular level. cDNA clones from the locus have been isolated and their sequence determined, confirming that Ace forms the structural gene for acetylcholinesterase (AChE). The cDNAs have a 1950 nucleotide open reading frame from which the complete amino acid sequence of AChE has been deduced. The Drosophila enzyme is found to have extensive homology to the known sequence of Torpedo AChE. Ace cDNAs have an unusual structure with a long 5' leader and several short upstream open reading frames.

Acetylcholinesterase↗
PubMed1985

A human acetylcholinesterase gene identified by homology to the Ace region of Drosophila.

The Ace locus of the Drosophila genome controls biosynthesis of the neurotransmitter-hydrolyzing enzyme acetylcholinesterase (acetylcholine acetylhydrolase, EC 3.1.1.7). We injected the mRNA species hybridizing with DNA fragments from this region into Xenopus oocytes, in which acetylcholinesterase mRNA is translated into active acetylcholinesterase. A 2.0-kilobase (kb) fragment of DNA from this region selectively hybridizes with Drosophila mRNA capable of inducing the biosynthesis of acetylcholinesterase in oocytes. This Drosophila DNA fragment cross-hybridized with human brain poly(A)+ RNA. We therefore used this DNA fragment as a probe for homologous sequence(s) in a human genomic DNA library and thus selected a 13.5-kb human DNA segment. DNA blot-hybridization revealed that a 2.6-kb fragment of this human DNA segment hybridizes with the Drosophila 2.0-kb DNA fragment. Both Drosophila and human fragments hybridized with a human brain mRNA species of about 7.0-kb that was barely detectable in the acetylcholinesterase-deficient HEp carcinoma. A fraction containing mRNA of similar size, extracted from human brain, induced acetylcholinesterase biosynthesis in oocytes. The human DNA fragment also was used in hybridization-selection experiments. In oocytes, hybrid-selected human brain mRNA induced acetylcholinesterase activity that was completely inhibited by 1,5-bis[4-allyldimethylammonium)phenyl]pentan-3-one dibromide but not by tetraisopropyl pyrophosphamide, a differential response to these inhibitors characteristic of "true" human brain acetylcholinesterase. These findings strongly suggest that both the Drosophila and the human DNA fragments are directly involved in controlling acetylcholinesterase biosynthesis.

Acetylcholinesterase↗
PubMed1984

Genetic activity along 315 kb of the Drosophila chromosome.

Transcripts from different tissues were mapped along a 315 kb segment of the Drosophila chromosome, a region which includes the rosy and Ace loci. Forty-three distinct RNA species were detected, though only 12 recessive lethal complementation groups had been mapped in the interval. The sum of the sizes of the transcripts covers 33% of the genomic DNA. The distribution of transcription units along the walk is very uneven. Sixty-three kb of genomic DNA at the proximal end of the walk encode 18 transcripts, while only seven are found in the next 153 kb. Each tissue exhibits a specific spectrum of transcripts. No clustering was seen among genes expressed coordinately. In salivary glands, the number of transcripts detected corresponds to the number of chromomeric units in the polytene chromosomes of this tissue. Moreover, the density distribution of transcripts along the DNA walk is parallel to the density distribution of chromomeric units.

Journal Article↗
PubMed1983

Transcripts, genes and bands in 315,000 base-pairs of Drosophila DNA.

We have mapped transcripts arising from 315,000 base-pairs of DNA from chromosome region 87D,E of Drosophila melanogaster. The DNA is represented in a series of overlapping recombinant phages; it constitutes about 14 bands in the polytene chromosome from 87D5,6 to 87E5,6 and contains the essential sequences for at least 12 complementation groups. We have defined 20 discrete polyadenylated RNA species transcribed from non-repetitive DNA in the region at various developmental stages. There is a generally good correlation between the position of transcription units, chromomeric units and complementation groups but with some significant exceptions. In particular, the two large bands in the region (E1,2 and E5,6) each contain several transcription units. We also find that a major part of a large band (E1,2) has no detectable transcripts and is apparently genetically silent.

Chromosome Banding↗
PubMed1983

Chromosomal walking and jumping to isolate DNA from the Ace and rosy loci and the bithorax complex in Drosophila melanogaster.

A chromosomal walk is described that covers 315 X 10(3) base-pairs of DNA from the 87DE region of the third chromosome of Drosophila melanogaster. The walk includes the DNA for the rosy and Ace loci, which code for xanthine dehydrogenase and acetylcholinesterase, respectively. Several dispersed repetitive elements were encountered in the walk. In every case, their positions in the chromosome differed in different strains, and so they are all presumed to be transposable elements. Several rearrangement breakpoints have been localized within the walk, including the break for In(3R) Cbx+R1 (87E1, 2-89E1, 2). One breakpoint fusion fragment of this inversion was isolated to jump from 87E into the cluster of homeotic genes of the bithorax complex, at 89E1-4.

Acetylcholinesterase↗
PubMed1983

Molecular mapping of genetic and chromomeric units in Drosophila melanogaster.

We have used a set of overlapping cloned segments defining a 315 kb (X 10(3) base-pairs) region of Drosophila melanogaster chromosomal DNA to map the sequences associated with the polytene band-interbands (chromomeric units) and with the lethal complementation groups contained within this region. The molecular map positions of the 13 +/- 1 chromomeric units from the 87D5-6 to 87E5, 6 region of the third chromosome were determined by in situ hybridization of selected segments to the polytene chromosomes. The length of the largest chromomeric unit within the 315 kb region is approximately 160 kb, while that for the smallest is less than 7 kb and may be as short as 3 kb. By mapping the breakpoints of deletions within the 315 kb region, we have located its 12 lethal complementation groups, which include the genes coding for acetylcholinesterase (Ace) and xanthine dehydrogenase (rosy). Comparison of the two molecular maps indicates a one-to-one topographical correlation between the genetic and chromomeric units.

Animals↗
PubMed1979

Cooperative interactions among protein and RNA components of the 50S ribosomal subunit of Escherichia coli.

Copperative interactions among constituents of the 50S ribosomal subunit of Escherichia coli have been analyzed in order to elucidate its assembly and structural organization. Proteins L5 and L18 were shown to be necessary and sufficient to effect the association of the 5S and 23S RNAs into a quaternary complex that contains equimolar amounts of all four components. Measurement of diffusion constants by laser light scattering revealed that integration of the 5S RNA induced the 23S RNA to adopt a somewhat more open conformation. An investigation of relationships among proteins associated with the central and 3' portions of the 23S RNA demonstrated that attachment of L5, L10 + L11, and L28 depends upon the RNA-binding proteins L16, L2, and L1 + L3 + L6, respectively, and that L2 interacts with the central segment of the 23S RNA. These data, as well as the results of others, have been used to construct a scheme that depicts both direct and indirect associations of the 5S RNA, the 23S RNA, and over two-thirds of the subunit proteins. The 5' third of the 23S RNA apparently organizes the proteins required to nucleate essential reactions, whereas a region within 500 to 1500 bases of its 3' terminus is associated primarily with proteins involved in the major functional activities of the 50S ribosomal particle.

Diffusion↗
PubMed1975

RNA-protein interactions in the ribosome. Binding of 50-S-subunit proteins to 5' and 3' terminal segments of the 23-S RNA.

Limited digestion of the Escherichia coli 50-S subunit permits the isolation of two large fragments of the 23-S RNA. One arises from the 5' end of the 23-S RNA and contains about 1200 nucleotides. The other arises from the 3' end of the 23-S RNA and contains about 2000 nucleotides. Each of the ten 50-S proteins known to bind specifically and independently to the 23-S RNA were tested for their ability to interact with these two RNA fragments. It was determined that the 5' terminal segment contains the specific binding sites for proteins L4, L20 and L24, whereas the 3' terminal segment contains the specific binding sites for proteins L1, L2, L3, L6, L13, L13 and L23.

Base Sequence↗
PubMedDate not supplied

Similar level of polyteny in bands and interbands of Drosophila giant chromosomes.

The giant polytene chromosomes of Drosophila melanogaster have long been of interest to the geneticist because of the visible map of the genome provided by their characteristic banding patterns. An issue in the understanding of the molecular basis of chromosome banding has been whether the chromosomal DNA is replicated to the same extent in bands and interbands. Although various suggestions have been put forward the point has remained controversial. We have isolated 315 kilobases (kb) of contiguous Drosophila genomic DNA which spans an interval of approximately 13 bands and interbands of the polytene chromosomes. We report here the measurement of the relative level of DNA replication in polytene chromosomes of 84 adjacent restriction fragments of our cloned DNA. We conclude that there are no significant differences in the level of polyteny within the large band and between bands and interbands of this region. This result supports the 'folded fibre' model of polytene chromosome organization, rather than models involving disproportionate replication along the banding pattern.

Animals↗