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Biomedical subjects

N Archidiacono

Publications and source records attributed to N Archidiacono.

At least 55 records · Page 3Linked to original sources

Ordered mapping of three alpha satellite DNA subsets on human chromosome 22.

We report the physical order of three alphoid DNA subsets on human chromosome 22 determined by a combination of low- and high-resolution cytological mapping. Multicolor fluorescence in situ hybridization was performed on metaphase chromosomes, interphase nuclei and extended chromatin preparations. The results visually demonstrate the presence of three distinct alphoid DNA domains at the centromeric region of chromosome 22. Two domains appear adjacent by extended chromatin hybridization, while the third one is separated by DNA that does not hybridize with any of our probes. Our data demonstrate the applicability of interphase mapping for ordering alpha satellite DNA repeat arrays. However, in our experiments, the relationship between the extremities of repeat arrays could only be studied by extended chromatin experiments.

Chromosome Mapping↗

A panel of subchromosomal painting libraries representing over 300 regions of the human genome.

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.

Animals↗

Comparative mapping of the actin-binding protein 280 genes in human and mouse.

Two genes encode actin-binding protein 280 isoforms. ABP-280 or filamin (FLN1) is present in the cytoskeleton of many cell types, whereas expression of FLN2 is limited to skeletal muscle and heart. FLN1 maps to human chromosome Xq28, and, by physical mapping in YAC clones, we have mapped the homologous murine locus (Fln1) to mouse chromosome X, in a region of syntenic homology with human chromosome X. We mapped FLN2 to human chromosome 7q32-q35 by analysis of somatic cell hybrids containing portions of chromosome 7, and, by using a mapping panel from an interspecific murine cross, we mapped the corresponding murine locus (Fln2) to murine chromosome 6 in a region homologous to human chromosome 7.

Animals↗

Hereditary motor and sensory neuropathy with calf hypertrophy is associated with 17p11.2 duplication.

The demyelinating type of hereditary motor and sensory neuropathy (HMSN I) is characterized by progressive weakness and atrophy of leg muscles. Six patients (age, 25-79 yr) belonging to three generations had calf hypertrophy (6 of 6), foot drop or difficulty with heel walking (4 of 6), pes cavus (3 of 6), absent or depressed tendon jerks in the lower limbs (4 of 6), and mild distal sensory loss (3 of 6). No other family member had leg atrophy. Motor conduction velocities ranged from 20 to 40 m/sec. Sural nerve biopsy showed loss of large myelinated fibers, numerous onion bulbs, and segmental demyelination and remyelination. Computed tomographic scans of leg muscles and histological and morphometric findings in gastrocnemius revealed true muscular hypertrophy. Southern blot and fluorescence in situ hybridization documented the duplication of the entire 17p11.2 segment associated with classical HMSN IA. The pathogenesis of muscle hypertrophy in our cases is unclear. Chronic leg muscle weakness and long-standing partial denervation might cause calf enlargement by a combination of compensatory "work-induced" and "stretch-induced" fiber hypertrophy. Alternatively, that all the affected family members presented calf hypertrophy might suggest the action of a genetic factor associated with the duplication at 17p11.2.

Adult↗

Characterization of chimpanzee-hamster hybrids by chromosome painting.

A panel of chimpanzee-human somatic cell hybrids was characterized by dual Alu-PCR of the chimpanzee DNA in the hybrid and subsequent hybridization of the labeled PCR products to human and chimpanzee chromosomes. In addition to the identification of the intact chimpanzee chromosomes retained in each hybrid, chromosome fragments were identified that will be useful in regional mapping. This technique also revealed the presence of centric inversions.

Animals↗

Cloning and comparative mapping of recently evolved human chromosome 22-specific alpha satellite DNA.

We have isolated and characterized a new alphoid probe, named p190.22. Its chromosomal location was investigated using fluorescence in situ hybridization. Under high stringency conditions p190.22 recognizes specifically the centromere of chromosome 22. A chromosome 22-specific alphoid subset has been previously reported in the literature (p22/1:2.1). The partial sequence and the genomic organization comparison strongly suggests that they recognize distinct subsets both specific for chromosome 22. The comparative mapping of probes p190.22 and p22/1:2.1 on chimpanzee (PTR and PPA) and gorilla (GGO) chromosomes was investigated. The two probes showed different hybridization results. p190.22, in particular, did not show any hybridization signal in these three species, suggesting a recent evolution.

Animals↗

Molecular organization and chromosomal location of human GC-rich heterochromatic blocks.

From the sequencing of three genomic DNA fragments and PCR amplification products from total human DNA, we have derived the sequence of a 545-bp Sau3A fragment (68% GC), representative of a family of human DNA repeats. Since previous studies suggested its linkage with unrelated Sau3A repeats of 68 bp (54% GC) (beta-satellite sequences), this feature was further investigated by in situ hybridization experiments and by Southern blot analysis of a panel of DNAs from human-Chinese hamster somatic cell hybrids. Both DNA repeats are preferentially localized on the heterochromatic regions of acrocentric chromosomes, on the pericentromeric heterochromatin of chromosome 1, 3 and 9, and on the proximal euchromatic region of the chromosome Y q arm. On chromosome 9, both repeats are part of a 2.7-kb higher-order repeat unit. These results and the Southern blot analysis on partial digests of total DNA, suggest that the linkage between the two repetitive DNA sequences is a constant feature throughout the genome. Furthermore, Southern blot analysis of HpaII-digested and MspI-digested DNA from different human tissues and tumor cell lines indicates that the investigated heterochromatic blocks appear to be subjected to changes in their methylation pattern.

Base Sequence↗

Cloning and comparative mapping of a human chromosome 4-specific alpha satellite DNA sequence.

We have isolated and characterized two human alphoid DNA clones: p4n1/4 and pZ4.1. Clone p4n1/4 identifies specifically the centromeric region of chromosome 4; pZ4.1 recognizes a subset of alphoid DNA shared by chromosomes 4 and 9. The specificity was determined using fluorescence in situ hybridization experiments on metaphase spreads and Southern blotting analysis of human-hamster somatic cell hybrids. The genomic organization of both subsets was also investigated. Comparative mapping on chimpanzee and gorilla chromosomes was performed. p4n1/4 hybridizes to chimpanzee chromosomes 11 and 13, homologs of human chromosomes 9 and 2q, respectively. On gorilla metaphase spreads, p4n1/4 hybridizes exclusively to the centromeric region of chromosome 19, partially homologous to human chromosome 17. No hybridization signal was detected on chromosome 3 of both chimpanzee and gorilla, in both species homolog of human chromosome 4. Identical comparative mapping results were obtained using pZ4.1 probe, although the latter recognizes an alphoid subset distinct from the one recognized by p4n1/4. The implications of these results in the evolution of centromeric regions of primate chromosomes are discussed.

Animals↗

A novel X-linked member of the human zinc finger protein gene family: isolation, mapping, and expression.

We report the partial characterization of a novel putative zinc finger gene of the Krüppel-type (ZNF81), isolated from an X Chromosome (Chr) specific library. The pattern of segregation in human-hamster somatic cell hybrids of sequences homologous to the ZNF81 finger domain has established that it resides within the Xp22.1-Xp11 region. ZNF81 represents yet another example, together with ZFX, ZNF41, and ZNF21, of members of the zinc finger gene family residing within the short arm of the human X Chr. Sequence analysis showed that ZNF81 may encode a polypeptide(s) containing tandem arrays of 12 canonical C2H2 zinc fingers of the Krüppel-type at the C-terminus. Northern analysis indicated that probes from the ZNF81 finger domain hybridize to polyadenylated transcripts present in several cell lines, a result that supports the hypothesis that it is an expressed, functional member of this multigene family.

Amino Acid Sequence↗

Isolation and comparative mapping of a human chromosome 20-specific alpha-satellite DNA clone.

We have isolated and characterized a human genomic DNA clone (PZ20, locus D20Z2) that identifies, under high-stringency hybridization conditions, an alphoid DNA subset specific for chromosome 20. The specificity was determined using fluorescence in situ hybridization. Sequence analysis confirmed our previously reported data on the great similarity between the chromosome 20 and chromosome 2 alphoid subsets. Comparative mapping of pZ20 on chimpanzee and gorilla chromosomes, also performed under high-stringency conditions, indicates that the alphoid subset has ancestral sequences on chimpanzee chromosome 11 and gorilla chromosome 19. However, no hybridization was observed to chromosomes 21 in the great apes, the homolog of human chromosome 20.

Animals↗

Mapping of human hexokinase 1 gene to 10q11----qter.

Two partial-length cDNAs encoding the type 1 human hexokinase (ATP:D-hexose 6-phosphotransferase) were isolated from a placenta cDNA library using a 50-bp oligonucleotide synthesized according to the known sequence of human HK1. Using the larger (1.8 kb) cDNA insert as a probe and a panel of human-hamster somatic cell hybrids, we were able to assign the HK1 gene to the long arm of chromosome 10.

Animals↗

Neuropsychological, psychiatric, and physical manifestations in 149 members from 18 fragile X families.

One hundred forty-nine subjects from 18 families with fragile X [fra(X)] syndrome were evaluated for their neuropsychological, psychiatric, and physical characteristics. The 36 fra(X) males had intelligence quotients ranging from less than 20 to 61, which prevented the delineation of a reliable neuropsychological profile. Behaviour fitted DSM-III-R and ADI diagnostic criteria of autism in only 2 subjects, both with very low intelligence level (IQ less than 20). Of 36 heterozygotes (HZ), 22 had an IQ between 20 and 80 and 14 between 81 and 99. The neuropsychological profile of the latter was compared with IQ-age-environment-matched 14 normal females and 14 normal males. Significantly poorer results in HZ were found on immediate digit memory and on Raven's progressive matrices (a visuo-spatial test of logical capabilities). The latter result, in conjunction with those results on the Bender visual-motor gestalt test and on some WAIS subtests, suggests a frequent deficit in spatial capabilities in such subjects. Such results tended to be confirmed by the profiles of the 22 HZ with IQ 20-80. No psychiatric abnormalities were found in HZ, except in one subject with IQ less than 20 which fitted DSM-III-R and ADI criteria for autism. Typical physical manifestations, especially cranio-facial, were more frequently present in the HZ group with lower IQ. Subnormal IQ was probably the most reliable abnormality for the detection of HZ in 49 females at 50% and 25% risk of heterozygosity.

Adolescent↗

Rett syndrome: exclusion mapping following the hypothesis of germinal mosaicism for new X-linked mutations.

The hypothesis of germinal mosaicism in the unaffected mother of two half-sisters affected with Rett syndrome is postulated to explain the unusual recurrence of this genetic disorder affecting only females (1/10,000); it might be caused by new X-linked mutations with lethality in male fetuses. The analysis of 34 X-linked restriction fragment length polymorphisms (RFLPs) in these two affected females and in their unaffected mother and half-brother, together with the reconstruction of phase for 15 informative RFLPs in somatic cell hybrids retaining a single X chromosome from each female, has made it possible to exclude some regions of the X chromosome as possible sites of the mutation(s) causing Rett syndrome.

Cell Line↗

Assignment of the gene for human tenascin to the region q32-q34 of chromosome 9.

Tenascin (TN) is a hexameric extracellular matrix glycoprotein that is highly expressed in solid tumors but has a restricted distribution in normal adult tissues. Each TN subunit is composed of segments with high homology to the sequences of epidermal growth factor, fibronectin and fibrinogen. Furthermore, it has been suggested that TN could modulate epithelial-mesenchymal and neuronal-glial interactions. Here, using a cDNA probe to human TN, we have carried out Southern blot analysis of the genomic DNAs from a panel of human-hamster somatic cell hybrids carrying different complements of human chromosomes. The results demonstrate that the human TN gene is located on chromosome 9. Furthermore, in situ hybridization studies demonstrate that human TN is located at 9q32-q34.

Animals↗

Isolation and expression analysis of a human zinc finger gene (ZNF41) located on the short arm of the X chromosome.

We have isolated a novel human zinc finger gene, ZNF41, from a human X-chromosome-specific library. Nucleotide sequence analysis reveals that ZNF41 potentially encodes a polypeptide featuring an array of 18 contiguous zinc fingers of the C2H2 type. Multiple polyadenylated transcripts homologous to ZNF41 are present at different levels in several distinct cell types. Southern analyses of somatic cell hybrids containing either intact or rearranged X chromosomes confirm the genomic origin of the isolated gene and establish that it is localized between Xcen and Xp22.1.

Amino Acid Sequence↗

A human chromosome 9-specific alphoid DNA repeat spatially resolvable from satellite 3 DNA by fluorescent in situ hybridization.

We have isolated a DNA clone (pMR9A) that identifies an alphoid DNA subset specific for chromosome 9. This alphoid subset is characterized by a dimeric organization as revealed by Southern blot analysis after digestion with HaeIII, HinfI, or StuI. Nonradioactive in situ hybridization demonstrated that pMR9A hybridizes only to the centromeric region of chromosome 9 and reveals chromosome 9 aneuploidies in interphase nuclei. In addition, the probe detects quantitative differences in alpha satellite DNA on chromosome 9, but these quantitative differences are not correlated with the size of the heterochromatic region. Double-labeling experiments, using a chromosome 9-specific satellite 3 clone and pMR9A, enabled us spatially to distinguish the alphoid and satellite 3 domains on metaphase chromosomes after treatment of the cultures with 5-azacytidine.

Aneuploidy↗