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Mapping of recombinants near the Huntington disease locus by using G8 (D4S10) and newly isolated markers in the D4S10 region.

Genetic linkage between the marker G8 (D4S10) and Huntington disease (HD) was studied in six Dutch pedigrees. The informativeness of the D4S10 locus was increased by isolation of a cosmid, C5.5, with a G8 subclone used as probe. We present a restriction map of 70 kb in the D4S10 region. Two subclones of C5.5, H5.52 and F5.53, detect MspI and SinI RFLPs, respectively. These probes increase the informativeness of D4S10 in the Dutch HD population from 55% to 95%. Seven recombinations were found in 124 informative meioses in which multipoint segregation of D4S10 haplotypes and the HD locus was studied. Two of the recombinations occurred within the D4S10 region. The other five recombinations are highly valuable for the mapping of present and future markers relative to each other and to the HD gene. In addition, several recombinations between markers in meioses from unaffected parents were noted, which will also be useful in ordering new markers. On the basis of our three-point recombination data, the orientation of the D4S10 region relative to HD is HD-H5.52-G8-F5.53, which independently confirms the previously derived polarity for D4S10.

Chromosome Mapping↗

An integrated metric physical map of human chromosome 19.

A metric physical map of human chromosome 19 has been generated. The foundation of the map is sets of overlapping cosmids (contigs) generated by automated fingerprinting spanning over 95% of the euchromatin, about 50 megabases (Mb). Distances between selected cosmid clones were estimated using fluorescence in situ hybridization in sperm pronuclei, providing both order and distance between contigs. An average inter-marker separation of 230 kb has been obtained across the non-centromeric portion of the chromosome. Various types of larger insert clones were used to span gaps between contigs. Currently, the map consists of 51 'islands' containing multiple clone types, whose size, order and relative distance are known. Over 450 genes, genetic markers, sequence tagged sites (STSs), anonymous cDNAs, and other markers have been localized. In addition, EcoRI restriction maps have been generated for > 41 Mb (approximately 83%) of the chromosome.

Base Sequence↗

Whole-genome shotgun optical mapping of Rhodobacter sphaeroides strain 2.4.1 and its use for whole-genome shotgun sequence assembly.

Rhodobacter sphaeroides 2.4.1 is a facultative photoheterotrophic bacterium with tremendous metabolic diversity, which has significantly contributed to our understanding of the molecular genetics of photosynthesis, photoheterotrophy, nitrogen fixation, hydrogen metabolism, carbon dioxide fixation, taxis, and tetrapyrrole biosynthesis. To further understand this remarkable bacterium, and to accelerate an ongoing sequencing project, two whole-genome restriction maps (EcoRI and HindIII) of R. sphaeroides strain 2.4.1 were constructed using shotgun optical mapping. The approach directly mapped genomic DNA by the random mapping of single molecules. The two maps were used to facilitate sequence assembly by providing an optical scaffold for high-resolution alignment and verification of sequence contigs. Our results show that such maps facilitated the closure of sequence gaps by the early detection of nascent sequence contigs during the course of the whole-genome shotgun sequencing process.

Chromosomes, Bacterial↗

High-resolution mapping of a 130-kb core region of the MYCN amplicon in neuroblastomas.

The MYCN proto-oncogene is amplified in 25% of neuroblastomas, and amplification is strongly correlated with advanced disease stage and with rapid tumor progression. We have generated a high-resolution restriction map of nearly 500 kb spanning the MYCN locus by subcloning yeast artificial chromosomes into cosmids. Cosmids plus additional amplified probes were hybridized to DNA from 33 MYCN amplified neuroblastomas, and we determined that the amplicons range from 350 kb to over 1 Mb. Deletions and rearrangements of the MYCN amplicon occurred less frequently in primary tumors than in cell lines. We have defined a 130-kb region that was amplified in 32 of 33 tumors. One additional tumor deleted 65 kb of this region from its amplicon, while amplifying a large amount of flanking DNA. The only CpG island found in this region was within the MYCN gene. In conclusion, our data demonstrate that, despite the large size of most amplicons, the core domain that is consistently amplified in neuroblastomas probably contains little more than the MYCN gene.

Chromosomes, Artificial, Yeast↗

Human tissue factor pathway inhibitor (TFPI) gene: complete genomic structure and localization on the genetic map of chromosome 2q.

Tissue factor pathway inhibitor (TFPI), a protease inhibitor that circulates in association with plasma lipoproteins (VLDL, LDL and HDL), helps to regulate the extrinsic blood coagulation cascade. We have cloned a 125-kb genomic region containing the entire human TFPI gene on six overlapping cosmids and prepared a restriction map of this contig to clarify gene structure. More than half (45 kb) of the 85-kb gene is occupied with 5' noncoding elements: coding begins at exon 3. A HindIII RFLP identified with one cosmid was genotyped in the CEPH panel of 59 reference families. Linkage analysis using markers on human chromosome 2 located the TFPI gene on 2q, 36 cM proximal to D2S43(pYNZ15) and 13 cM distal to the crystalline gamma-polypeptide locus CRYGP1(p5G1).

Base Sequence↗

A physical genome map of the Burkholderia cepacia type strain.

Burkholderia cepacia (basonym Pseudomonas cepacia), the type species of the new genus Burkholderia, is of interest, not only because of its broad catabolic capacity and its ability to antagonize soil-borne plant pathogens, but also because of its causative role in infections in man, which are particularly evident in patients with cystic fibrosis. A physical map of the 8.1 Mb genome of the B. cepacia type-strain ATCC 25416 was constructed by applying two-dimensional pulsed-field gel electrophoresis techniques. Placed onto the macrorestriction map were 38 SpeI, 11 SwaI, 11 PacI, 11 PmeI and six I-CeuI sites, resulting in an average resolution of 105 kbp. Random single-hit linearization by irradiation and restriction mapping uncovered the presence of four circular replicons of 3.65 Mb, 3.17 Mb, 1.07 Mb and 200 kbp in size. The largest replicon harbours four rrn operons while the other two Megabase-size replicons each contain a single rrn operon, suggesting that the genome has three chromosomes and a large plasmid. Within the beta subdivision of proteobacteria, the existence of multiple replicons is not confined to B. cepacia. The phylogenetically related species Burkholderia glumae, Burkholderia pickettii, Burkholderia solanacearum, Alcaligenes eutrophus and the so far unassigned Pseudomonas glathei were also found to harbour more than one Megabase-size replicon.

Base Sequence↗

The Saccharomyces cerevisiae SIN3 gene, a negative regulator of HO, contains four paired amphipathic helix motifs.

The SIN3 gene (also known as SDI1) is a negative regulator of the yeast HO gene. Mutations in SIN3 suppress the requirement for the SWI5 activator for expression of the yeast HO gene and change the normal asymmetric pattern of HO expression in mother and daughter cells. Furthermore, the in vitro DNA-binding activity of several DNA-binding proteins is reduced in extracts prepared from sin3 mutants. We have cloned the SIN3 gene and determined that a haploid strain with a SIN3 gene disruption is viable. We determined the sequence of the SIN3 gene, which is predicted to encode a 175-kDa polypeptide with four paired amphipathic helix motifs. These motifs have been identified in the myc family of helix-loop-helix DNA-binding proteins and in the TPR family of regulatory proteins. The SIN3 transcript was mapped, and it was determined that the SIN3 transcript was absent in stationary-phase cells. Immunofluorescence microscopy with anti-SIN3 antibody demonstrated that SIN3 protein was present in nuclei. A comparison of restriction map and sequence data revealed that SIN3 is the same as regulatory genes UME4 and RPD1.

Amino Acid Sequence↗

Mitochondrial and ribosomal DNA variation among members of the Anopheles quadrimaculatus (Diptera: Culicidae) species complex.

The extent of intra- and inter-specific variation in mitochondrial DNA and nuclear ribosomal RNA gene restriction sites was determined for the four sibling species of the Anopheles quadrimaculatus complex. Individual mosquitoes were identified by allozyme analysis according to previously published keys, and the total genomic DNA of these same individuals was then cleaved with restriction enzymes. Restriction maps of mitochondrial DNA, including the positions of variable sites, were constructed for each species. No evidence for interspecific hybridization was found in the populations surveyed. There was little variation in restriction patterns within any given species, but differences occurred among the four. Three restriction enzymes (AvaI, HindIII, and PvuII) yielded species-specific DNA restriction patterns for the mitochondrial DNA, while AvaI and HindIII produced diagnostic patterns for the ribosomal DNA. Thus, restriction patterns were very useful for detecting cryptic species but less appropriate than isozymes for studying genetic structure of populations within species.

Animals↗

Molecular genetics of human erythrocyte MiIII and MiVI glycophorins. Use of a pseudoexon in construction of two delta-alpha-delta hybrid genes resulting in antigenic diversification.

Human glycophorins alpha and delta (or A and B) specify the MNSs blood group antigens; they exhibit considerable structural variation among populations. We show that two variant phenotypes of Miltenberger class III and VI are encoded by similar hybrid glycophorin genes in a delta-alpha-delta arrangement. Restriction mapping identified altered fragments unique to the MiIII and MiVI genes. Genomic sequences spanning exons 2 to 4 of the two genes were obtained by allele-specific polymerase chain reaction. Restriction analysis and direct sequencing of the amplified DNA revealed that MiIII and MiVI genes are identical to the delta gene except that, in both, an internal segment of the delta gene has been replaced by its homologous counterpart of the alpha gene, resulting in a delta-alpha-delta hybrid structure. In the process of hybrid formation a portion of alpha exon 3 and intron 3, that carries a functional 5' splicing signal, has been fused to an exon-like sequence in the delta gene that retains a 3' but lacks a 5' splicing signal. These rearrangements created a composite exon resulting in the expression of the ordinarily unexpressed delta gene sequence and conferred the hybrid proteins with new antigenic specificities. The expression of this sequence in MiIII glycophorin is directly demonstrated by protein sequencing. MiIII and MiVI genes differ in the location of upstream (delta-alpha) and downstream (alpha-delta) breakpoints and in the length of sequence replacement. The delta-alpha breakpoints of the two genes occur at different locations within a 35-base pair sequence of exon 3 that is clustered with multiple inverted repeats, whereas the alpha-delta breakpoints reside downstream in two dissimilar blocks of sequences of intron 3. The minimal length of the delta gene sequence that has been replaced by the alpha gene is 55 base pairs in the MiIII gene and 131 base pairs in the MiVI gene. Such segmental DNA transfers may have proceeded unidirectionally through the mechanisms of gene conversion.

Amino Acid Sequence↗

[Cloning and nucleotide sequence determination of the fus gene coding for the elongation factor G of Thermus thermophilus HB8].

A clone with the Thermus thermophilus HB8 fus gene coding for elongation factor G has been identified in a genomic library in plasmid pBR 322 by hybridization with labeled oligonucleotide 19 bases that are complementary in length to the 3'-end of the T. thermophilus fus gene. The fragment with the fus gene was recloned into the pTZ 18R plasmid. A restriction map of this fragment has been made. A set of short overlapping fragments of the fus gene has been obtained by nucleotide sequence unspecific linearization of the plasmid and by the restriction fragment subcloning into M13 mp18 and mp19 vectors. The nucleotide sequence of the fus gene was determined by the dideoxy chain termination method. Fus gene codes the elongation factor G 690 amino acids in length (Mr = 76756 Da). The amino acid sequence of EF-G from T. thermophilus has a 59.7% homology with that of E. coli and a 29.0% homology with EF-2 of rat liver.

Amino Acid Sequence↗

Organisation of the equine immunoglobulin constant heavy chain genes. II. Equine cgamma genes.

The number of immunoglobulin G constant heavy chain genes (cgamma genes) varies broadly among mammalian species, reflecting structural and functional differences between expressed immunoglobulin G (IgG) isotypes and allotypes. Up to now equine IgG isotypes have been defined only at the biochemical and serological level. It is still not clear how many IgG isotypes exist in horses and whether there are any allotypes. Here, we describe the isolation and characterisation of equine cgamma genes. An equine genomic lambda phage library was screened with a human cgamma4 probe. Cross-hybridising equine cgamma sequences were cloned twice and characterised by restriction mapping with the human cgamma4 and a murine sgamma1 probe. Genomic equine DNA probes for both, cgamma genes and corresponding switch regions (sgamma), were isolated and used for a more detailed BamHI restriction analysis, comparing genomic DNA of various horses. This analysis reveals the existence of at least five, or probably six cgamma genes in the equine haploid genome. Beside the porcine system, this is the highest number of cgamma genes described for any mammalian species. Moreover, for two of these cgamma genes, BamHI restriction fragment length polymorphism became evident.

Animals↗

A restriction endonuclease cleavage map of mouse mitochondrial DNA.

A restriction endonuclease cleavage map is presented for mouse mitochondrial DNA. This map was constructed by electron microscopic measurements on partial digests containing fixed D-loops, and by electrophoretic analysis of partial and complete single enzyme digests, and of double digests. No map differences were detected between mitochondrial DNA from cultured LA9 cells and an inbred mouse line for the six endonucleases used. Three cleavage sites recognized by HpaI, five sites recognized by HincII, two sites recognized PstI and four sites recognized by BamI were located with respect to the origin of replication and the EcoRI and HinIII sites previously determined by others. No cleavages were produced by KpnI or SalI. The migration of linear DNA with a molecular weight greater than 1 X 10(6) was not a linear function of log molecular weight in 1% agarose gels run at 6.6 volts/cm.

Animals↗

Mapping the heterogeneous DNA region that determines the nine A alpha mating-type specificities of Schizophyllum commune.

Classical genetic studies identified nine mating-type specificities at the A alpha locus of the Basidiomycete fungus Schizophyllum commune. We have used Southern blot hybridizations to generate EcoRI restriction maps of the A alpha locus for 18 strains, including all nine specificities. A alpha 1, A alpha 3 and A alpha 4 DNA was subcloned from three cosmids and used as probes. A unique region of DNA was found for each of the three cloned specificities. Hybridization was detected in this region only if the probe(s) and the blotted genomic DNAs were from strains with the same A alpha specificity. DNAs from strains with the same A alpha specificity hybridize regardless of geographic origin, but DNAs from strains with different A alpha specificities do not cross-hybridize. The results demonstrate two size classes of unique A alpha DNA. This unique DNA is about 4.5 kb in A alpha 1 strains and about 7.0-8.5 kb in other strains. Transcription regulators Z and Y, which were deduced previously from the DNA sequence of the A alpha 1, A alpha 3 and A alpha 4 loci, are probably encoded by all non-A alpha 1 loci. The smaller A alpha 1 loci appear to encode only Y and lack sequence for Z. No evidence was found for a locus that encodes only Z. The lack of hybridization detected between A alpha loci with different specificities suggests that the evolution of A alpha has resulted from extensive sequence divergence.

Blotting, Southern↗

Isolation and characterization of a plasmid from phase I Coxiella burnetii.

The DNA from the Nine Mile phase I strain of Coxiella burnetti, the etiological agent of Q fever, has been isolated and purified by cesium chloride-ethidium bromide density gradient centrifugation. A fraction of this DNA has a density characteristic of plasmid DNA. The plasmid DNA was cut with 20 different restriction endonucleases and shown to be a discrete entity. The plasmid, designated QpH1, is approximately 36 kilobases in size and has a molecular mass of 2.4 x 10(7) daltons. A partial restriction map of QpH1 has been constructed by using the restriction endonucleases SalI, KpnI, PstI, and XbaI. QpH1 DNA radioactively labeled by nick translation was used to show that sequences similar to the plasmid are also present in the phase II antigenic variant of C. burnetii.

Centrifugation, Density Gradient↗

[A study on restriction of the areas working in speech function--application of multivariate analysis of aphasia test data and of lesions on CT images, by composing a "restricted-aphasia-lesion-map"].

Computed tomography (CT) gave a large contribution to morphological analysis of the aphasia syndromes. The aphasia problems are, however, still controversial and have many unresolved issues, even from a morphological point of view. In most cases with cerebral vascular lesion causing speech dysfunction, we are able to define an extent of density change on CT images. But its extent seems to be often not consistent with the area supposed to be deranged in functional work-up of speech. CT appearance of some areas may be little changed or normal when those areas are to be in poor condition in their functional maintenance. This may be due to such a vascular supply which permits brain tissues to be sustained but which does not work for their function to be normally performed. From 642 cases with cerebral vascular lesion we reviewed CT images of 382 cases: 171 cases having a lesion in the left hemisphere and 46 of them showing aphasia syndrome; 151, a lesion in the right hemisphere alone and 3, aphasic; and 60 cases having lesions on both sides and 7 showing aphasia syndrome. First, we determined anatomically the extent of CT change in 102 cases, all right-handed, with a lesion in the left hemisphere. The extents were piled and made up to a "non-aphasia-lesion-map". This map was used for eliminating those areas as not working in speech function. The other map of the areas was made out of CT images of aphasia cases (33 cases including one agraphia). The latter map was put upon the "non-aphasia-lesion-map", so that the very area working in speech function could be more restricted. The third map, "restricted-aphasia-lesion-map" demonstrated those areas related to speech function: (1) the region limited around the three rami in the Sylvian fissure (Broca A); (2) the inferior frontal gyrus and the posterior aspect of the middle frontal gyrus (Broca B); (3) the inferior aspect of the cortex and subcortex of the Reil's island; (4) most of the middle temporal gyrus, the posterior third of the superior temporal gyrus, a large portion of the supramarginal gyrus and a part of the limbic system; (5) a large portion of the limbic system; (6) the anterior aspect of the superior frontal gyrus; and (7) the corpus callosum. The Standard Language Test for Aphasia (SLTA) was applied for 33 cases of aphasia.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗

Conservation of chromosomal arrangement among three strains of the genetically unstable archaeon Halobacterium salinarium.

Phenotypic variants of Halobacterium salinarium NRC-1 arise at a frequency of 10(-2). These result from transpositions of halobacterial insertion sequences and rearrangements mediated by halobacterial insertion sequences. We have tested the hypothesis that such mutations are confined to only a portion of the genome by comparing the chromosomal restriction map of H. salinarium NRC-1 and that of the derivative S9, which was made in 1969. The two chromosomes were mapped by using two-dimensional pulsed-field gel electrophoresis and the restriction enzymes AflII, AseI, and DraI. A comparison of the two deduced maps showed a domain of about 210 kbp to be subject to many rearrangements, including an inversion in S9 relative to NRC-1. However, the rest of the chromosome was conserved among NRC-1, S9, and an independent Halobacterium isolate, GRB, previously mapped by St. Jean et al. (A. St. Jean, B. A. Trieselmann, and R. L. Charlebois, Nucleic Acids Res. 22:1476-1483, 1994). This concurs with data from eubacteria suggesting strong selective forces maintaining gene order even in the face of rearrangement events occurring at a high frequency.

Blotting, Southern↗

Molecular cloning and physical mapping of the tupaia herpesvirus genome.

Purified virion DNA of about 200 kilobase pairs of tupaia herpesvirus strain 2 was cleaved with EcoRI or HindIII restriction endonuclease. Restriction fragments representing the complete viral genome including both termini were inserted into the EcoRI, HindIII, and EcoRI-HindIII sites of the bacterial plasmid pAT153. Restriction maps for the restriction endonucleases EcoRI and HindIII were constructed with data derived from Southern blot hybridizations of individual viral DNA fragments or cloned DNA fragments which were hybridized to either viral genome fragments or recombinant plasmids. The analysis revealed that the tupaia herpesvirus genome consists of a long unique sequence of 200 kilobase pairs and that inverted repeat DNA sequences of greater than 40 base pairs do not occur, in agreement with previous electron microscopic data. No DNA sequence homology was detectable between the tupaia herpesvirus DNA and the genome of murine cytomegalovirus, which was reported to have a similar structure. In addition, seven individual isolates of tupaia herpesvirus were characterized. The isolates can be grouped into five strains by their DNA cleavage patterns.

Animals↗

The human ribonuclease/angiogenin inhibitor is encoded by a gene mapped to chromosome 11p15.5, within 90 kb of the HRAS protooncogene.

Ribonuclease/angiogenin inhibitor (RAI) is a tight-binding inhibitor of ribonucleolytic and angiogenic activities involved in tumor progression. It is translated from various mRNAs differing in their 5 regions and originating from a single gene locus. Recently, this gene (RNH) has been assigned to 11p15.5, the terminal part of the short arm of chromosome 11. The regional chromosomal localization was confirmed by somatic cell and in situ hybridization and further refined by long-range restriction mapping. The data place RNH within 90 kb of the Harvey-ras protooncogene (HRAS), so far the most telomeric gene on 11p, in a region involved in growth regulation and tumor development.

Chromosome Mapping↗