ISSN:1424-8581    

DOI:10.1159/000133875

出版商:S. Karger AG    

年代:1995

数据来源: Karger

ISSN:1424-8581    

DOI:10.1159/000133876

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

We have cytogenetically characterized a hatchery stock of gilthead seabream, Sparus aurata. The study included larvae, juveniles and adults. In S. αurαtα (diploid chromosome number 2n = 48), a pair of NORs is located at the ends of the short arms of the first submetacentric pair of chromosomes. In this stock we discovered a polymorphism which affects the NORs, and, by means of several cytogenetic and molecular techniques, we demonstrate that this polymorphism is due to the complete deletion of one of the two NORs in a high number of individuals. The significance of these cytogenetic characteristics for this species are discussed since they may be the source of aquaculture proble

ISSN:1424-8581    

DOI:10.1159/000133877

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

Pulmonary surfactant, a lipoprotein complex is essential for normal lung function. The non-serum surfactant-associated proteins, SP-A, SP-B, and SP-C, play important roles in the biology of pulmonary surfactant. We have mapped the human SP-B gene (SFTP3) to chromosome 2, band 2p12→p11.2 by fluorescent in situ hybridizatio

ISSN:1424-8581    

DOI:10.1159/000133878

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

Chronological aging of women is clearly associated with an increase in both X-chromosome loss and micronuclei formation in peripheral lymphocytes. It has been suggested that micronucleus formation is an important mechanism of chromosome loss. In the present study, fluorescence in situ hybridization was used to study micronuclei content in two age groups (women below 30 and above 50 years old). A probe for centromeric alphoid consensus sequences (SO-αAllCen) and a cloned X-specific centromeric probe (pXBR) were separately used to detect the presence of any chromosomes and the X chromosome, respectively. The presence of centromere-positive micronuclei was significantly higher among the older donors (51.5%) than among the younger donors (34.3%). The X chromosome was highly overrepresented in the micronuclei, the older women showing a higher proportion of X-positive micronuclei (24.0%) than the younger women (14.0%). Assuming that the rest of the centromere-positive micronuclei contained autosomes, a significant age-dependent difference was also noted for micronuclei harboring autosomes (27.5 % among the older women and 20.3 % among the younger women). These findings suggest that both the X chromosome and autosomes are responsible for the age-dependent increase of micronuclei in women’s peripheral lymphocyt

ISSN:1424-8581    

DOI:10.1159/000133879

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

A region-specific library of human chromosome 2p23→p21 was constructed using microdissection and micro-cloning techniques. Analysis of 94 single-copy microclones from the library showed that 64% were derived from the dissected region. Ten microclones were further mapped to the 2p21 region using a patient with an interstitial deletion of 2p21 and displaying holoprosencephaly, an abnormal embryonic development in midbrain and midfac

ISSN:1424-8581    

DOI:10.1159/000133880

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

The genetic map location of the recently discovered imprinted gene U2afbpL has been verified and refined in several mouse crosses. RI strain analysis had previously shown that the gene is located on mouse chromosome 11. This assignment has been verified using interspecific backcrosses. Moreover, the location of the gene relative to a fixed order of markers in the proximal region of mouse chromosome 11 has been established. The location of the gene on mouse chromosome 11 corresponds to a homologous linkage group that is conserved on human chromosome 5q. The location of the human homologue has been determined using both somatic cell hybrid genetic analysis and fluorescence in situ hybridization. These analyses have mapped the human locus U2AFBPL to human chromosome 5q23→q3

ISSN:1424-8581    

DOI:10.1159/000133881

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

DNA samples from about 100 human-hamster somatic cell hybrids, previously characterized by conventional banding techniques, were amplified with dual-Alu PCR. The products were then used as probes in FISH experiments on normal human metaphases for an accurate cytogenetic characterization of the human material retained in each hybrid. In addition to entire chromosomes, most hybrids were found to contain one or a few chromosome fragments, as a result of rearrangements that had occurred in vitro. Forty additional primary hybrids, in which conventional cytogenetic analysis failed to reveal any complete human chromosome, contained many human chromosome fragments. More than 300 chromosome fragments were scored and their precise chromosomal location recorded. We show data indicating that subchromosomal painting libraries generated from these hybrids can be favorably used in the fine characterization of chromosomal rearrangements encountered in clinical cytogenetics or in tumor cytogenetics, and in tracking chromosomal changes that occurred in primate evolution.

ISSN:1424-8581    

DOI:10.1159/000133882

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

After transfection of amplification-promoting DNA elements into mammalian cells, homogeneously staining regions (HSRs) are formed by high copy numbers of transfected DNA arranged in head-to-tail polymers. Here, we wanted to evaluate the stability of this type of HSR during prolonged cultivation of transfected cells in selective medium. Thymidine kinase-deficient mouse L cells were transfected with pAPR4tk DNA harboring the amplification-promoting element 4 (APR4) linked to the gene for thymidine kinase (TK) or, alternatively, transfected with a DNA construct (pAPR4t-PA) carrying, in addition, the expression cassette for human tissue-type plasminogen activator (t-PA). After transfection, one or two HSRs per cell were formed that disintegrated spontaneously after 25–40 wk of continuous cultivation in the presence of selective HAT (hypoxanthine-aminopterin-thymidine) medium. Unexpectedly, plasmid DNA reinserted into a plethora of new chromosomal sites, as revealed by in situ hybridization and Southern blot analysis. Coincidently, secretion of t-PA decreased to 10–20% of its original level. After transfection of pAPR4tk DNA lacking the t-PA expression cassette, HSR decay and reintegration of plasmid constructs into multiple chromosomal sites were also observed, whereas the ptk vector without an amplification-promoting DNA element did not form an HSR after transfection. We conclude that, in contrast to the pattern of known structures with head-to-tail arrangements, the HSR formed by amplification-promoting DNA elements represents a novel type of HSR that disintegrates by transposition into a plethora of new chromosomal integration sites. This process is mediated by the amplification-promoting DNA element itself and can be observed even when selective pressure is maintai

ISSN:1424-8581    

DOI:10.1159/000133883

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

A recently identified gene encoding a metalloprotease-like, disintegrin-like, cysteine-rich protein (MDC) represents a candidate tumor suppressor gene for human breast cancer based on its location within a minimal region of chromosome 17q21 previously defined by tumor deletion mapping. The work reported here has shown that the MDC gene consists of 28 exons interrupted by relatively short introns, most of them 67 bp to 5 kb in length. We have identified two forms of transcripts generated by alternative splicing. The more abundant form encodes a protein of 769 amino acids; the other, a previously described cDNA, encodes 524 amino acids. Exons 1a, 1b, 1c, 1d, and 2–7 encode a proprotein domain; exons 7–13, a metalloprotease-like domain; exons 14–17, a disintegrin domain; exons 18–22, a cysteine-rich domain, including an epidermal growth factor (EGF)-like repeat domain within exons 21 and 22; exon 23, a transmembrane domain; and exons 24 and 25, a short cytoplasmic domain. These results show that human MDC contains a mosaic of exons capable of encoding several functional

ISSN:1424-8581    

DOI:10.1159/000133884

出版商:S. Karger AG    

年代:1995

数据来源: Karger