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At least 397 records · Page 22Linked to original sources
PubMed1993

Cosmid mapping and locus linkage within the human chromosomal region 22q13.1.

Many human meningiomas show loss of heterozygosity at distal loci but retain constitutional heterozygosity at one or more proximal loci of 22q. Molecular analysis indicted deletions involving at least the region 22q12.3-qter. In this region, distal to myoglobin, the putative meningioma locus ought to be expected. Long-range mapping was performed around two loci from 22q12.3-q13.1 (D22S16 and PDGFB, the most proximal locus to be lost in meningioma). D22S16, originally assigned to 22q13-qter by isotopic in situ hybridization, was placed in the vicinity of PDGFB by utilizing a set of somatic cell hybrids, an assignment confirmed by fluorescence in situ hybridization (FISH) of a cosmid clone containing the D22S16 locus. Moreover, pulsed field gel electrophoresis suggests a close linkage of both markers within 630 kb.

Arachnoid↗
PubMed1994

Fluorescence in situ hybridization analysis using cosmid probes to define chromosome 6q abnormalities in ovarian carcinoma cell lines.

Deletion of 6q is a frequent finding in ovarian carcinoma, which would suggest that this region contains one or more putative tumor suppressor genes. Chromosome 6q abnormalities in six ovarian carcinoma cell lines were analyzed by G-banding and fluorescence in situ hybridization (FISH). Using a variety of probes, including a chromosome 6 paint, a probe specific for the chromosome 6 centromere, and cosmids that map to q24 (cCI6-115), q25 (cCI6-4), q26 (cCI6-91, cCI6-119), and q27 (cCI6-13, cCI6-24, and cCI6-111), abnormalities of 6q were found in three cell lines. In cell line OAW42 (hypotetraploid), the sequences complementary to cCI6-119, cCI6-91, and cCI6-13 probes were lost in two homologues of chromosome 6, which indicates the deletion of genetic material from bands q26-27. The same bands were translocated in cell line PEO1 (hypertriploid). The probes from this region were absent on two copies of chromosome 6, but hybridized to two or three markers. In cell line 59M (hyperdiploid) an interstitial deletion proximal to q24 was detected in one chromosome 6. We conclude that it is very likely that a gene or genes localized in bands 6q26-27, and perhaps in the region proximal to 6q24, play a critical role in the development or progression of ovarian carcinoma.

Adenocarcinoma↗
PubMed1985

Construction of novel shuttle vectors and a cosmid vector for the glutamic acid-producing bacteria Brevibacterium lactofermentum and Corynebacterium glutamicum.

Novel cloning vectors for glutamic acid-producing bacteria have been constructed. Two cryptic plasmids, pAM330 from Brevibacterium lactofermentum and pHM1519 from Corynebacterium glutamicum, were used as precursors, and recombined with pBR325 or pUB110. Resultant composite plasmids were able to propagate and to express the CmR or KmR phenotype in B. lactofermentum and C. glutamicum. A smaller, high-copy-number plasmid, pAJ43, was also isolated following deletion of a part of the pAM330-pBR325 composite plasmid. Furthermore, a cosmid vector, which can be packaged and transduced through phage infection, has been developed using a cohesive-end fragment of the f1A phage and plasmid pAJ43. These plasmids are suitable for use as cloning vectors in the glutamic acid-producing bacteria.

Brevibacterium↗
PubMed1986

Spontaneous insertions into cosmid vector: a warning.

During the course of characterization of a human genomic library we found that some of the selected pNNL cosmid clones carried only very short inserts. In addition, several clones that did contain full-length inserts were found to be unstable and generated repeated deletions of various portions of their inserts. Moreover, all the clones examined displayed rearrangements in the vector portions. The rearranged clones that were characterized by restriction mapping were found to have deletions starting between ClaI and HindIII in the region of the cos segment of the pNNL vector used in the construction of the library. We determined the nucleotide sequence of the 1300-bp EcoRI-PvuII segment located in the cos region, and by the computer search we found that it contains Escherichia coli insertion elements IS1.

Base Sequence↗
PubMed1987

Lorist6, a cosmid vector with BamHI, NotI, ScaI and HindIII cloning sites and altered neomycin phosphotransferase gene expression.

Four new features have been included in a phage-lambda-replicon-based cosmid vector, Lorist6. A ScaI restriction site allows insertion of blunt-ended DNA, partially digested with AluI or any other restriction enzyme which creates blunt ends after cleavage. NotI and BamHI sites enable construction of libraries using double digestion with NotI + Sau3AI. The promoter of the neo gene has been substituted by a promoter derived from the tet gene of pBR322, increasing expression of the resistance gene product. A transcriptional terminator has been placed downstream from the neo gene to prevent transcription into insert DNAs.

Cloning, Molecular↗
PubMed1987

A family of cosmid vectors with the multi-copy R6K replication origin.

A family of cosmid vectors was constructed which contain replication origins (ori) derived from the multicopy plasmid R6K, a kanamycin resistance gene and two cos sites, permitting efficient library construction. Additional features of later constructs are (i) the presence of NotI sites flanking the site of insertion to allow intact excision of inserts, (ii) the facility for selective cloning of the ends of inserts for rapid chromosome walking, and (iii) the use of a mutated R6K ori leading to an increased copy number.

Bacteriophage lambda↗
PubMed1987

An efficient mobilizable cosmid vector, pRK7813, and its use in a rapid method for marker exchange in Pseudomonas fluorescens strain HV37a.

We describe the construction and utilization of a new mobilizable cosmid vector. Using this vector, mobilizable libraries of bacterial DNA can be efficiently made without a need for size fractionation of target DNA. The low stability of this vector in Pseudomonas fluorescens makes it useful in a rapid strategy, which is not dependent on plasmid incompatibility, for recombining transposon-induced mutations into the bacterial chromosome.

Cosmids↗
PubMed1988

Smart2, a cosmid vector with a phage lambda origin for both systematic chromosome walking and P-element-mediated gene transfer in Drosophila.

We describe a new phage-lambda-replicon-based cosmid vector suitable for both chromosome walking and P-element-mediated transformation in Drosophila. Its unique BamHI cloning site is flanked by the promoters for the SP6 and T7-encoded RNA polymerases, permitting the synthesis of probes complementary to the ends of the cloned inserts for library screening. The selectable marker is tet for bacterial cell transformation and neo for Drosophila transformation expressed under the control of the Drosophila hsp70 promoter.

Animals↗
PubMed1992

A versatile shuttle cosmid vector for use in Escherichia coli and actinomycetes.

A shuttle cosmid vector has been constructed for Escherichia coli and actinomycetes. This vector, pFD666, utilizes the origin of replication (ori) of the broad-host-range plasmid, pJV1, from Streptomyces phaeochromogenes, for replication in actinomycetes and is compatible with vectors derived from pIJ101. The pFD666 vector employs the neomycin phosphotransferase-encoding gene (neo) from transposon Tn5 as the selective marker. To achieve this, the native promoter of neo was replaced by one optimized for expression in both hosts. The polylinker used for cloning has nine unique sites flanked by the promoters for T7 and SP6 RNA polymerase for the production of specific RNA probes. Terminators on both sides of the polylinker protect the vector from transcription originating from cloned inserts. An M13 ori allows the production of single-stranded DNA.

Actinomycetales↗
PubMed1995

A new mobilizable cosmid vector for use in Vibrio cholerae and other gram-negative bacteria.

A new mobilizable cosmid vector, pCOS5, was engineered for use in Vibrio cholerae (Vc). Plasmid pCOS5 is small in size (7286 bp), contains the oriT from plasmid RK2, and has several unique restriction sites. The complete nucleotide sequence of pCOS5 was deduced from the DNA fragments used in its construction. Biparental matings using Escherichia coli (Ec) SM10 and triparental matings using Ec DH5 alpha[pRK2013] were used to measure the conjugation frequency of pCOS5 and pAJM1, a clone containing a 40-kb insert of chromosomal DNA from Vc ligated into pCOS5. Transfer of pCOS5 or pAJM1 to Vc occurred at a frequency of between 10(-2)-10(-3) transconjugants per recipient cell. The promiscuous nature of RP4/RK2 transfer functions makes pCOS5 a potentially useful vector for mobilizing large fragments of cloned DNA between different Gram- bacteria that support replication of ColE1 plasmids or as a mobilizable suicide vector in Gram- bacteria where replication of ColE1 plasmids is not supported.

Base Sequence↗
PubMed1994

Conjugal transfer of cosmid DNA from Escherichia coli to Saccharopolyspora spinosa: effects of chromosomal insertions on macrolide A83543 production.

Cosmid pOJ436, containing large inserts of Saccharopolyspora spinosa (Ss) DNA, was transferred by conjugation from Escherichia coli to Ss an integrated into the chromosome, apparently by homologous recombination, at high frequencies (10(-5) to 10(-4) per recipient). Transfer was mediated by the plasmid RP4 (RK2) transfer functions in E. coli, and the RK2 oriT function located on pOJ436 [Bierman et al., Gene 116 (1992) 43-49]. pOJ436 lacking Ss DNA, or containing a small insert (approx. 2 kb) of Ss DNA, conjugated from E. coli and integrated at either of two bacteriophage phi C31 attB sites at low frequency (approx. 10(-7) per recipient). Exconjugants containing homologous inserts or inserts at the phi C31 attB sites were stable in the absence of antibiotic selection, and most produced control levels of tetracyclic macrolide A83543 factors. Some exconjugants contained similar kinds of large deletions and were defective in macrolide production.

Anti-Bacterial Agents↗
PubMed1996

New cosmid vectors for library construction, chromosome walking and restriction mapping in filamentous fungi.

New cosmid vectors were constructed for the ascomycete fungus, Magnaporthe grisea and the basidiomycete fungus, Ustilago maydis. These vectors are capable of transforming M. grisea at frequencies of up to 5 transformants/micrograms linear DNA and U. maydis at up to 25 transformants/microgram circular DNA for integrative transformation. In addition, 2800 transformants/microgram DNA are possible when using an autonomously replicating vector. Since the promoters used in these vectors function in other ascomycete and basidiomycete fungi, we anticipate that these vectors will be widely applicable.

Ascomycota↗
PubMed1989

A cosmid clone map derived from a small region of human chromosome 11.

We have used cosmid "fingerprinting" to construct an overlapping DNA clone "map" of the human DNA in a mouse/human hybrid cell line, E65-9, that contains about 4 x 10(6) bp, including the H-Ras gene, as its human component. We have additionally used 32P-labeled RNA probes to establish linkage of particular sets of clones, and the final map comprises about 300,000 bp and is contained in three nonoverlapping segments. The reasons for failure to close the gaps by direct probing are discussed. We have developed techniques to search for rare cutting restriction enzyme cleavage sites in large numbers of cloned DNAs and have positioned sites for EagI and BssHII on our clone map. The methods we used are capable of considerable scale-up and are currently being applied to the short arm of human chromosome 11.

Animals↗
PubMed1989

The proximity of DNA sequences in interphase cell nuclei is correlated to genomic distance and permits ordering of cosmids spanning 250 kilobase pairs.

The physical distance between DNA sequences in interphase nuclei was determined using eight cosmids containing fragments of the Chinese hamster genome that span 273 kb surrounding the dihydrofolate reductase (DHFR) gene. The distance between these sequences at the molecular level has been determined previously by restriction enzyme mapping (J.E. Looney and J.L. Hamlin, 1987, Mol. Cell Biol. 7: 569-577; C. Ma et al., 1988, Mol. Cell Biol. 8: 2316-2327). Fluorescence in situ hybridization was used to localize the DNA sequences in interphase nuclei of cells bearing only one copy of this genomic region. The distance between DNA sequences in interphase nuclei was correlated to molecular distance over a range of 25 to at least 250 kb. The observed relationship was such that genomic distance could be predicted to within 40 kb from interphase distance. The correct order of seven probes was derived from interphase distances measured for 19 pair-wise combinations of the probes. Measured distances between sequences approximately 200 kb apart indicate that the DNA is condensed 70- to 100-fold in hybridized nuclei relative to a linear DNA helix molecule. Cell lines with chromosome inversions were used to show that interphase distance increases with genomic distance in the 50-90 Mb range, but less steeply than in the 25-250 kb range.

Animals↗
PubMed1990

A 195-kb cosmid walk encompassing the human Xq28 color vision pigment genes.

By using cosmid walking, we have cloned a 195-kb region from chromosome band Xq28 that encompasses the red and green color pigment genes and 85 kb of flanking sequences. This has allowed us to confirm that the color pigment genes are within very homologous units arranged in tandem array. Each unit contains two BssHII sites and one NruI site that are frequently methylated in male leukocyte DNA. A NotI and an EagI site are present 6 kb upstream from the red pigment gene promoter; the NotI site was shown to be unmethylated in the active X chromosome in leukocytes and may represent a CpG island for the whole cluster. We have identified another CpG island, 61 kb 3' from the last green pigment gene, that is unmethylated in leukocytes on the active X chromosome, but methylated on the inactive X. This island is flanked by sequences conserved in evolution and may thus correspond to an expressed gene. We also describe an informative three-allele restriction fragment length polymorphism within the pigment gene cluster.

Biological Evolution↗
PubMed1995

A 500-kilobase region containing the tuberous sclerosis locus (TSC1) in a 1.7-megabase YAC and cosmid contig.

A complete overlapping clone map of a 1.7-Mb region from DBH to D9S67 that includes the TSC1 candidate region has been constructed. The map includes YAC and cosmid clones, contains STS approximately every 50 kb on average, and establishes the order of five previously unordered loci. The overall physical length of this segment of chromosome 9q34 (1.7 Mb) is significantly less than expected compared to its estimated genetic length (approximately 10 cM). Consequently, the physical length of the TSC1 candidate region is substantially less than predicted by a genetic distance of approximately 2 cM.

Base Sequence↗