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The construction of human somatic cell hybrids containing portions of the mouse X chromosome and their use to generate DNA probes via interspersed repetitive sequence polymerase chain reaction.

Interspersed repetitive sequence polymerase chain reaction (IRS-PCR) has become a powerful tool for the rapid generation of DNA probes from human chromosomes present in rodent somatic cell hybrids. We have constructed a somatic cell hybrid containing a major portion of the mouse X chromosome in a human background (clone 8.0). IRS-PCR was developed for the specific amplification of mouse DNA using either of two primers from the rodent-specific portion of the murine B1 repeat. Amplification was subsequently performed with clone 8.0 and a subclone, 8.1/1, which retains a small murine X-chromosomal fragment including Hprt and the Gdx locus. A total of 15-20 discrete PCR products ranging in size from less than 500 to greater than 3000 bp were obtained from clone 8.0 with each primer. In clone 8.1/1, a subset of these bands plus some additional bands were observed. Nine bands amplified from clone 8.1/1 have been excised from gels and used as probes on Southern blots. All of the fragments behaved as single-copy probes and detected domesticus/spretus variation. They have been regionally mapped using an interspecific backcross. The probe locations are compatible with those of markers known to be present in clone 8.1/1. These results demonstrate the feasibility of this method as applied to the mouse genome and the high likelihood of generating useful DNA probes from a targeted region.

Animals↗

Bovine DNA contains a single major family of interspersed repetitive sequences.

A major family of short, interspersed, repeated sequences in the bovine genome has been characterized. This family makes up the majority of all non-satellite repetitive DNA or about 6% of the bovine genome. It is estimated that there are at least 600 000 copies of this family interspersed among non-repetitive DNA sequences. Sequence analysis shows that this family includes sequences reported previously by Watanabe et al. (Nucleic Acids Res. 10, 1459-1469, 1982) and is distantly related to the human Alu sequence family.

Animals↗

Periodically interspersed repetitive sequences may govern higher-order DNA coiling in chromatin and chromosomes.

The interspersed periodic arrangement of repetitive and unique sequences in eukaryotic DNAs is proposed as the underlying molecular basis for higher-order DNA coiling in chromatin and mitotic chromosomes. It is assumed that (i) two types of interspersed repetitive sequences are distributed strictly periodically throughout the genome, splitting the single copy DNA into short and long periods respectively in such a pattern that each long period is composed of a definite number of short periods and repeats, (ii) the short and long periods make the turn lengths of the solenoid and supersolenoid structures respectively determining their diameters; (iii) specific proteins interact with each type of repeats making cross ties between nearby repeats of each class helping to form, constrain, and stabilize the solenoid and the supersolenoid structures: (iv) the long period may be equated with the basic chromomere unit. The model predicts: (i) splitting of contiguous genes by inserted repetitive sequences; and (ii) two types of genomes differing in the hierarchy of DNA coiling.

Animals↗

Large-scale cloning of human chromosome 2-specific yeast artificial chromosomes (YACs) using an interspersed repetitive sequences (IRS)-PCR approach.

We report here an efficient approach to the establishment of extended YAC contigs on human chromosome 2 by using an interspersed repetitive sequences (IRS)-PCR-based screening strategy for YAC DNA pools. Genomic DNA was extracted from 1152 YAC pools comprised of 55,296 YACs mostly derived from the CEPH Mark I library. Alu-element-mediated PCR was performed for each pool, and amplification products were spotted on hybridization membranes (IRS filters). IRS probes for the screening of the IRS filters were obtained by Alu-element-mediated PCR. Of 708 distinct probes obtained from chromosome 2-specific somatic cell hybrids, 85% were successfully used for library screening. Similarly, 80% of 80 YAC walking probes were successfully used for library screening. Each probe detected an average of 6.6 YACs, which is in good agreement with the 7- to 7.5-fold genome coverage provided by the library. In a preliminary analysis, we have identified 188 YAC groups that are the basis for building contigs for chromosome 2. The coverage of the telomeric half of chromosome 2q was considered to be good since 31 of 34 microsatellites and 22 of 23 expressed sequence tags that were chosen from chromosome region 2q13-q37 were contained in a chromosome 2 YAC sublibrary generated by our experiments. We have identified a minimum of 1610 distinct chromosome 2-specific YACs, which will be a valuable asset for the physical mapping of the second largest human chromosome.

Animals↗

Absence of short-period repetitive-sequence interspersion in the basidiomycete Schizophyllum commune.

Reassociation kinetics and electron microscopy were used to examine the organization of DNA sequences in the Basidiomycete Schizophyllum commune. Short-period interspersion of repetitive and unique sequences is absent from the DNA of this wood-rotting fungus. Instead, repetitive sequences are found predominantly in several, perhaps 16, clusters averaging 225 kilobases in length. The results of this study, the first concerning a fungus in the important fungal Class Basidiomycetidae, are discussed in relation to: sequence organization in three other species of true fungi, fungal evolution and the regulation of gene expression.

Agaricales↗

Adaptation of the interspersed repetitive sequence polymerase chain reaction to the isolation of mouse DNA probes from somatic cell hybrids on a hamster background.

A strategy for the rapid isolation of DNA probes from radiation-fusion Chinese hamster cell hybrids containing overlapping portions of the murine X chromosome based on the interspersed repetitive sequence polymerase chain reaction (IRS-PCR) previously used with human somatic cell hybrids has been developed. This specific amplification of mouse DNA on a hamster background depends on the use of primers directed to the B2 short interspersed repeat element family and the R repeat, from the long interspersed repeat element family, L1. Two sets of amplification conditions, which gave specific amplification of mouse DNA from either a mouse X-monochromosomal hybrid or irradiation-fusion hybrids having reduced X content, were defined. The mouse X-only chromosome hybrid yielded approximately 20 discrete reproducible bands, while the irradiation-fusion hybrids yielded between 1 and 10 discrete products. Comparison of different irradiation-fusion hybrids has allowed the definition of both specific and shared products corresponding to different regions within the overlapping X-chromosome fragments present within these hybrids. Use of such hybrids and the IRS-PCR technique has allowed the isolation of probes corresponding to the central region of the mouse X chromosome that contains the X-inactivation center. The method should be widely applicable to the isolation of mouse DNA sequences from mouse hybrid cell lines on either human or Chinese hamster backgrounds.

Animals↗

Rapid isolation of DNA probes within specific chromosome regions by interspersed repetitive sequence polymerase chain reaction.

A method was recently developed for the specific amplification of human DNA sequences from interspecific somatic cell hybrids by the polymerase chain reaction (PCR) using primers directed to Alu, a short interspersed repeat element (SINE). We now show human-specific amplification using a primer to the 3' end of the human long interspersed repeat element L1Hs (LINE). A monochromosomal hybrid containing an intact human X chromosome yielded approximately 25 discrete products, ranging in size from 800 to 4500 bp. Combination of a single Alu primer and the L1Hs primer yielded a large number of smaller products (300-1000 bp) distinct from those observed with either primer alone. Inspection of ethidium bromide-stained gels showed one Alu-Alu and three Alu-L1Hs products which were present in an intact X chromosome but absent in a hybrid containing an X chromosome deleted for the single metaphase band q28. These four fragments were isolated from the gel and used as probes on Southern blots which confirmed their localization to Xq28. These results demonstrate that primers can be constructed to a variety of interspersed repetitive sequences (IRS) and used individually or in combination for the rapid isolation of DNA fragments from defined chromosomal regions by IRS-PCR.

Animals↗

Efficient high-resolution genetic mapping of mouse interspersed repetitive sequence PCR products, toward integrated genetic and physical mapping of the mouse genome.

The ability to carry out high-resolution genetic mapping at high throughput in the mouse is a critical rate-limiting step in the generation of genetically anchored contigs in physical mapping projects and the mapping of genetic loci for complex traits. To address this need, we have developed an efficient, high-resolution, large-scale genome mapping system. This system is based on the identification of polymorphic DNA sites between mouse strains by using interspersed repetitive sequence (IRS) PCR. Individual cloned IRS PCR products are hybridized to a DNA array of IRS PCR products derived from the DNA of individual mice segregating DNA sequences from the two parent strains. Since gel electrophoresis is not required, large numbers of samples can be genotyped in parallel. By using this approach, we have mapped > 450 polymorphic probes with filters containing the DNA of up to 517 backcross mice, potentially allowing resolution of 0.14 centimorgan. This approach also carries the potential for a high degree of efficiency in the integration of physical and genetic maps, since pooled DNAs representing libraries of yeast artificial chromosomes or other physical representations of the mouse genome can be addressed by hybridization of filter representations of the IRS PCR products of such libraries.

Animals↗

Application of interspersed repetitive sequence polymerase chain reaction for construction of yeast artificial chromosome contigs.

Construction of physical maps across candidate regions is one of the rate-limiting steps of positional cloning projects. To date, most physical maps have been constructed by polymerase chain reaction (PCR)-based sequence-tagged site (STS) content mapping. While effective, this technique has a number of disadvantages including problems with yeast artificial chromosome (YAC) chimerism, the time and effort required to generate new STSs from YAC ends, the cost of primer synthesis for large contiging projects, and the time, effort, and expense necessary for screening each STS in the two-tiered hierarchical YAC library screening format. An alternative strategy, interspersed repetitive sequence (IRS) PCR genomics, alleviates many of these constraints. Clonal overlap is detected by hybridization of individual IRS-PCR products to IRS-PCR product pools of the three-dimensional coordinate pools of YAC libraries in dot-blot format. Entire libraries can be screened in a single step, and multiple libraries can be screened simultaneously. Cloning YAC fragments, sequencing, and primer generation are eliminated, increasing the efficiency of contig construction and reducing the expense. In addition, the genomic location of the individual IRS-PCR products can also be simultaneously determined by screening either interspecific backcrosses or radiation hybrid panels, in dot-blot format, confirming contig extension in the region of interest.

Animals↗

A highly repetitive interspersed sequence isolated from genomic DNA of the Medaka, Oryzias latipes, is conserved in three other related species within the genus Oryzias.

A highly repeated interspersed sequence (OLR1) was isolated from a genomic DNA library of the Medaka, Oryzias latipes. The OLR1 was about 160 base pairs (bp) in length. As judged from the results of colony hybridization experiments, OLR1 is one of the major repeated DNA sequences in the Medaka genome and is present in every 136 kb on average. Results of Southern and colony-hybridization analyses indicate that OLR1 is a small interspersed repetitive element (SINE). OLR1-related sequences were conserved in other three species (O. luzonensis, O. curvinotus, and O. mekongnensis) within the genus Oryzias as a repetitive sequence. These results lend support at the DNA level to the hypothesis that these four species form one group in the genus Oryzias, as has been suggested from an analysis of their karyotypes (Magtoon and Uwa, '85, Proc. Jpn. Acad., Ser. B, 61:157-160).

Animals↗

A PCR technique based on the Hip1 interspersed repetitive sequence distinguishes cyanobacterial species and strains.

The use of primers based on the Hip1 sequence as a typing technique for cyanobacteria has been investigated. The discovery of short repetitive sequence structures in bacterial DNA during the last decade has led to the development of PCR-based methods for typing, i.e., distinguishing and identifying, bacterial species and strains. An octameric palindromic sequence known as Hip1 has been shown to be present in the chromosomal DNA of many species of cyanobacteria as a highly repetitious interspersed sequence. PCR primers were constructed that extended the Hip1 sequence at the 3' end by two bases. Five of the 16 possible extended primers were tested. Each of the five primers produced a different set of products when used to prime PCR from cyanobacterial genomic DNA. Each primer produced a distinct set of products for each of the 15 cyanobacterial species tested. The ability of Hip1-based PCR to resolve taxonomic differences was assessed by analysis of independent isolates of Anabaena flos-aquae and Nostoc ellipsosporum obtained from the CCAP (Culture Collection of Algae and Protozoa, IFE, Cumbria, UK). A PCR-based RFLP analysis of products amplified from the 23S-16S rDNA intergenic region was used to characterize the isolates and to compare with the Hip1 typing data. The RFLP and Hip1 typing yielded similar results and both techniques were able to distinguish different strains. On the basis of these results it is suggested that the Hip1 PCR technique may assist in distinguishing cyanobacterial species and strains.

Bacterial Proteins↗

Interspersed repetitive sequence (IRS)-PCR for typing of whole genome radiation hybrid panels.

The typing of a radiation hybrid (RH) panel is generally achieved using a unique primer pair for each marker. We here describe a complementing approach utilizing IRS-PCR. Advantages of this technology include the use of a single universal primer to specify any locus, the rapid typing of RH lines by hybridization, and the conservative use of hybrid DNA. The technology allows the mapping of a clone without the requirement for STS generation. To test the technique, we have mapped 48 BAC clones derived from mouse chromosome 12 which we mostly identified using complex probes. As mammalian genomes are repeat-rich, the technology can easily be adapted to species other than mouse.

Animals↗

Rapid and efficient construction of yeast artificial chromosome contigs in the mouse genome with interspersed repetitive sequence PCR (IRS-PCR): generation of a 5-cM, > 5 megabase contig on mouse chromosome 1.

We have developed a new technique for the generation of YAC contigs in the mouse genome that is based on the ability to detect overlapping clones by hybridization of shared IRS-PCR products. As a demonstration of the technique, a 5-cM, > 5 megabase contig was developed on the distal half of mouse Chromosome (Chr) 1, spanning the region from Lamb2 to At3. The contig covers roughly 5% of the genetic distance of the chromosome and is comprised of more than 80 clones; 71 probes were assigned physical order to the chromosome, of which 59 were new markers generated in this study. Eight of the new probes were shown to be polymorphic between C3H/HeJ-gld and M. spretus. Three probes were mapped on a [(C3H/HeJ-gld x M. spretus) x C3H/HeJ-gld] interspecific backcross to integrate the physical map with a high-resolution genetic map of the region.

Animals↗

Structure and function of an AT-rich, interspersed repetitive sequence from Chironomus thummi: solenoidal DNA, 142 bp palindrome-frame and homologies with the sequence for site-specific recombination of bacterial transposons.

Chironomus thummi thummi contains a repetitive AT-rich 118 bp sequence mainly in the centromere regions and elsewhere in the genome (1). A large cluster of repeats is regularly present in the non-transcribed spacer of rDNA. Dimers and multimers of the repeat migrate slower in small pore gels than would be expected from their size. The results indicate a solenoidal structure with a coil girth of appr. 350 bp. This structure is most probably due to a highly periodic positioning of di-nucleotides of the type purine - purine or pyrimidine-pyrimidine with distances of appr. 10 bases. In a cluster of 118 bp repeats, regions of dyad-symmetry are positioned such that a 142 +/- 2 bp palindrome-frame is generated. Evidence is presented favouring the assumption that the repeat functions primarily in sister chromatid exchange.

Adenine↗

Toward the construction of integrated physical and genetic maps of the mouse genome using interspersed repetitive sequence PCR (IRS-PCR) genomics.

Using two recently developed techniques, IRS-PCR YAC walking and IRS-PCR genotyping, a framework-integrated physical and genetic map of the mouse genome was constructed. The map consists of 821 contigs, containing 7746 YAC clones originating from three different YAC libraries. Three hundred eighty of the contigs have been anchored to the genetic map. Approximately 16% of the physical length of the mouse genome is estimated to be represented.

Animals↗