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S S Potter

Publications and source records attributed to S S Potter.

At least 73 records · Page 4Linked to original sources
PubMed1988

Overlapping transcriptional units on the same strand within the murine beta-glucuronidase gene complex.

We have identified and partially characterized a complex transcriptional unit within the murine beta-glucuronidase gene complex on chromosome 5. On the same strand and within the first intron of the beta-glucuronidase structural gene, Gus-s, we observe an RNA polymerase II promoter motif. That sequences within this carefully defined region can promote RNA polymerase II transcription is supported by results of in vitro transcriptional runoff assays and by expression of a linked reporter gene in both cultured cells and transgenic mice. Results of RNA blot hybridization and S1 nuclease protection studies reveal a 2.2-kilobase processed liver transcript which is initiated just downstream of the promoter motif and sharing little, if any, sequence with the 2.7-kilobase beta-glucuronidase mRNA. Both RNA species are found in liver where beta-glucuronidase is known to be expressed in all cell types. To our knowledge, this is the first description of eukaryotic mRNAs from overlapping transcription units which share the same strand yet exhibit little, if any, sequence similarity. A possible regulatory relationship between these overlapping structural genes is discussed.

Animals↗
PubMed1988

Legless, a novel mutation found in PHT1-1 transgenic mice.

In this report it is shown that the PHT1-1 line of transgenic mice exhibited a pattern of developmental abnormalities when the mice were homozygous for the transgene insertion. Hindlimbs were uniformly truncated at the distal end of the femur, resulting in a "legless" appearance. Forelimbs lacked anterior structures including digits and the radius. The brains had many defects, particularly in the anterior structures of the cerebrum, including the olfactory lobes. Craniofacial malformations in the form of facial clefts also commonly occurred. Furthermore, heterozygotes of this line, with only one copy of the DNA insertion, and other transgenic lines carrying the same DNA construct appeared normal, suggesting that in the PHT1-1 line a gene significant in mammalian development has been disrupted.

Animals↗
PubMed1988

Distinct subfamilies of primate L1Gg retroposons, with some elements carrying tandem repeats in the 5' region.

Two subfamilies of L1 elements, differing dramatically in the first 1.2 kb of sequence at their 5' ends, were identified in the prosimian primate, Galago garnetti. Interesting patterns of sequence similarity were observed between the galago subfamilies, and with the L1s from human and from another prosimian, the slow loris. Furthermore, members of one of the subfamilies have six to eight tandemly repeated units of 73 bp, starting about 730 bp from their 5' ends. Such tandem repeats have not been reported in other primate L1s, but a striking sequence similarity was found between the galago tandem repeats and those previously described at the 5' termini of some mouse L1s [Loeb, D. D. et al. Mol. Cell. Biol. 6, 168-182, 1986]. Although the similar sequence indicates a shared, conserved function, the galago repeats are sub-terminal and therefore cannot serve as portable RNA polymerase II promoters, as has been suggested for the mouse tandem repeats.

Animals↗
PubMed1988

Mys retrotransposons in Peromyscus leucopus and transgenic Mus musculus.

The mys family of retrotransposons exhibits an interesting phylogenetic distribution with 500-1000 copies per haploid genome in the white-footed mouse Peromyscus leucopus and no copies detectable in the house mouse Mus musculus, even though most other repeated sequences are shared by these two species. Comparison of the DNA sequences from the 3' ends of five mys elements show that insertion occurs just upstream of a well-conserved 11 bp target sequence. Transcription patterns of the elements in brain, liver, heart, kidneys and gonads in Peromyscus leucopus are analyzed. Transcripts are found in all tissues examined, but they are remarkably heterogeneous in size. When four cloned elements are introduced into transgenic Mus musculus, however, discrete patterns of expression are revealed. Furthermore, a study of the structure of the concatemers of mys elements in the transgenic mice demonstrates that recircularization of injected linear molecules is an important event in concatemer generation.

Animals↗
PubMed1987

Phylogenetic screening of the human genome: identification of differentially hybridizing repetitive sequence families.

The phi-screen, a method of phylogenetic screening, can be employed to detect repetitive sequence families that differentially hybridize between closely related species. Such differences may involve sequence divergence or variations in copy number, including total presence versus absence of a family of repeated DNA. We present the results of a phi-screen comparing the human genome to that of the prosimian, Galago crassicaudatus. Three human repetitive families that are divergent or not present in galago have been detected. One of these families is described in detail; it is similar among the anthropoids but is present in a lower copy number and/or divergent form in prosimians. The family is clearly related to the transposon-like human element (THE) described by Paulson et al. (1985). THEs have long terminal repeats reminiscent of retroviruses but are unique in that they have no sequence similarity to known mammalian retroviruses. The sequence of a solo long terminal repeat, found unassociated with THE internal sequence, is presented. This family member, THE p2, is bordered by a 5-bp target-site repeat and is interrupted by the insertion of an Alu element. A solo THE element sequenced by Wiginton et al. (1986) contains an insertion of Alu at precisely the same position as does THE p2.

Animals↗
PubMed1985

Characterization of cloned human alphoid satellite with an unusual monomeric construction: evidence for enrichment in HeLa small polydisperse circular DNA.

A recombinant DNA plasmid library was constructed from HeLa cell extrachromosomal circular DNA and the sequence organization of one family of clones, which contain sequences enriched in HeLa small polydisperse circular (spc) DNA, was studied by restriction mapping and base sequence analysis. Restriction mapping revealed each clone to be composed solely of imperfect tandem repeats of ca. 170 bp. The entire DNA sequence of one clone was determined and found to be alphoid satellite with a variant monomeric construction.

Base Sequence↗
PubMed1985

Distinct characteristics of loop sequences of two Drosophila foldback transposable elements.

A few foldback (FB) transposable elements have, between their long terminal inverted repeats, central loop sequences which have been shown to be different from FB inverted repeat sequences. We have investigated loop sequences from two such FB elements by analyzing their genomic distribution and sequence conservation and, in particular, by determining if they are normally associated with FB elements. One of these FB loop sequences seems to be present in a few conserved copies found adjacent to FB inverted repeat sequences, suggesting that it represents an integral component of some FB elements. The other loop sequence is less well-conserved and not usually associated with FB inverted repeats. This sequence is a member of another family of transposable elements, the HB family, and was found inserted in an FB element only by chance. We compare the complete DNA sequences of two HB elements and examine the ends of four HB elements.

Animals↗
PubMed1985

L1 sequences in HeLa extrachromosomal circular DNA: evidence for circularization by homologous recombination.

Subcloned probes of the L1 family of repetitive elements were used to isolate L1-carrying clones from a plasmid library of HeLa cell extrachromosomal circular DNA. One clone was analyzed in detail by restriction mapping, cross-hybridization to L1 probes, and base sequence analysis. In addition to approximately the 3' half of a full-sized L1 element, this clone carried 390 base pairs of non-L1 sequence that is single copy in the HeLa genome. A HeLa genomic clone of this unique chromosomal region was isolated and the sequence organization of the circle clone was compared with the linear chromosomal region from which it was ultimately derived. We discuss possible mechanisms of circular DNA formation and propose homologous intrachromosomal recombination between 9-base-pair direct repeats to be most likely in this case.

Chromosome Deletion↗
PubMed1984

Rearranged sequences of a human Kpn I element.

The complete nucleotide sequence of a human Kpn I element inserted into alpha-satellite DNA is presented. This sequence reveals several features of interest. First, a large block of DNA normally associated with Kpn I elements has been deleted. Second, the order of the remaining sequences is permuted in a manner that cannot be accounted for by simple inversion. Third, a significant open reading frame of 675 bases is detected.

Base Composition↗
PubMed1983

Unusual domains of human alphoid satellite DNA with contiguous non-satellite sequences: sequence analysis of a junction region.

The sequence organization of cloned segments of Human DNA carrying unusual domains of alphoid satellite was studied by restriction mapping, electron microscopy and base sequence analysis. In some cases restriction mapping revealed the absence of the typical 340 bp EcoR 1 dimer, although blot hybridizations showed the extensive presence of alphoid satellite. A variant monomeric construction was demonstrated by DNA sequencing. Furthermore, inverted repeats within these domains were detected by electron microscopy. In one case these were shown to be the result of interruptions in the satellite sequence by members of a family of repetitive, conserved elements.

Base Sequence↗
PubMed1982

DNA sequence analysis of a Drosophila foldback transposable element rearrangement.

The complete nucleotide sequence of a DNA rearrangement associated with the foldback 4 (FB 4) transposable element is presented. The results demonstrate that the entire loop sequence and almost all of one of the inverted terminal repeats is absent. Moreover, the sequence of the remaining inverted repeat suggests that the FB elements might undergo inversions via recombinations between the two inverted repeats of a single element.

Base Sequence↗
PubMed1981

Unusual structure of the FB family of transposable elements in Drosophila.

We have analyzed the construction of the members of the foldback (FB) family of transposable elements in Drosophila by detailed restriction analysis, cross hybridization, electron microscopy, in situ hybridization and nucleotide sequence determination. The members are heterogeneous, with both the inverted terminal repeats and the total element sizes extremely variable. Nevertheless, the ends of the inverted repeats represent closely conserved sequences, similar for all members. Sequence analysis of one of the FB elements revealed an unusual constriction. There are scattered multiple copies of a 10 bp sequence near the inverted repeat termini; 300 bp from the end this sequence is expanded to a 20 bp repeat, and 500 bp from the end it is again expanded to a 31 bp repeat. A large part of the inverted repeats consists of contiguous tandem repeats of this 31 bp sequence. We also find two differences between the two copies of the inverted repeat, one of which involves an intact copy of the 10 bp sequence mentioned above. Sequence analysis of a corresponding DNA segment without this transposable element shows that insertion generates a 9 bp duplication at the target site. In situ hybridizations to polytene chromosomes show about 30 widely scattered positions with homology. Comparison of the hybridization patterns for three strains shows significant interstrain and intrastrain differences in chromosomal locations.

Animals↗
PubMed1979

Transposition of elements of the 412, copia and 297 dispersed repeated gene families in Drosophila.

The stability of elements of three different dispersed repeated gene families in the genome of Drosophila tissue culture cells has been examined. Different amounts of sequences homologous to elements of 412, copia and 297 dispersed repeated gene families are found in the genomes of D. melanogaster embryonic and tissue culture cells. In general the amount of these sequences is increased in the cell lines. The additional sequences homologous to 412, copia and 297 occur as intact elements and are dispersed to new sites in the cell culture genome. It appears that these elements can insert at many alternative sites. We also describe a DNA sequence arrangement found in the D. melanogaster embryo genome which appears to result from a transposition of an element of the copia dispersed repeated gene family into a new chromosomal site. The mechanism of insertion of this copia element is precise to within 90 bp and may involve a region of weak sequence homology between the site of insertion and the direct terminal repeats of the copia element.

Animals↗
PubMed1977

Two-dimensional restriction analysis of the Bacillus subtilis genome: gene purification and ribosomal ribonucleic acid gene organization.

With two-dimensional restriction enzyme analysis we have been able to cleave the Bacillus subtilis genome and resolve the resulting deoxyribonucleic acid (DNA) segments into discrete bands on agarose gels. A general procedure for gene purification has been developed by coupling multidimensional restriction analysis with a biological assay for gene detection. The organization of ribosomal ribonucleic acid (rRNA) genes was studied by hybridizing 16S and 23S rRNA probes to the two-dimensional DNA banding patterns.

Bacillus subtilis↗