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W B Frommer

Publications and source records attributed to W B Frommer.

58 records · Page 4Linked to original sources
PubMed1989

A class II patatin promoter is under developmental control in both transgenic potato and tobacco plants.

A new member of the patatin gene family belonging to the class II subfamily was isolated and characterized by DNA sequencing. In order to study the expression profile of this gene, the promoter was fused to the beta-glucuronidase gene and transferred to potato and tobacco. Histochemical analysis revealed high expression in a few defined cells in potato tubers and in a specific layer of both potato and tobacco root tips. In contrast to the developmentally and metabolically regulated class I patatin gene B33 this gene was not inducible by elevated levels of sucrose. Expression of this chimaeric gene was also found in callus and suspension cultures of potato.

Base Sequence↗
PubMed1988

DNase I hypersensitive sites in the 5'-region of the maize Shrunken gene in nuclei from different organs.

The chromatin structure of the 5'-upstream region of the Shrunken (Sh) gene in Zea mays has been examined. We have identified a region of DNase I hypersensitivity extending at least from the 3'-end of exon 1 for 2 kb into the 5'-flanking region. This region is composed of a set of closely spaced hypersensitive sites separated by small regions that are less accessible to DNase I. The most sensitive sites are located within 300 bp upstream of the transcription start site. Hypersensitive sites are found essentially at the same positions in kernels, roots and leaves, although the latter display different relative intensities. No changes are found in roots within the tested region upon anaerobic induction. Testing protein-free plasmid DNA containing the 5' upstream region of the Sh gene, we found a site sensitive to the single strand specific nuclease S1 located very close to a DNase I hypersensitive site identified in chromatin. Several hypersensitive sites are flanking in vitro binding sites of nuclear proteins as determined by Werr et al. (1988; accompanying paper).

Base Sequence↗
PubMed1985

Structure of the sucrose synthase gene on chromosome 9 of Zea mays L.

The structure of the shrunken gene of Zea mays encoding sucrose synthase (EC 2.4.1.13) was determined by (i) sequencing the transcription unit and 1.2 kb of 5' -upstream sequences from a genomic clone, (ii) by sequencing a nearly full length cDNA clone and (iii) by determining the transcription start site by a combination of primer extension experiments with synthetic oligodeoxynucleotide primers and S1 mapping. The sucrose synthase gene is 5.4 kb long, of which 2746 bp are found in the mature mRNA. The gene is interrupted by 15 introns. The first two introns are 1 kb and 0.5 kb in length, respectively, while the other introns are much smaller. A TATA box is located 30 bp upstream from the transcription start site. Approximately 610 bp upstream of the transcription start site a direct repeat of 16 nucleotides, separated by a 4-fold repetition of the sequence GGTGG is detected. The 16-bp sequence has similarities to a sequence repeat found between two promoters of a maize zein gene also expressed in the endosperm tissue. The transposable element Ds in the mutant sh-m5933 and sh-m6233 alleles is inserted in the seventh and first intron, respectively. The genomic and cDNA clones were obtained from different maize lines. This allows the determination of polymorphic sites which are frequent in 3rd codon position and absent in 1st and 2nd codon positions. In addition, the 3' -untranslated sequence shows two duplications that may have arisen by the insertion and subsequent excision of transposable elements.

Journal Article↗