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Study of human chromosomes. IV. Labeling of chromosomal proteins with the amino group specific fluorescent reagent fluorescamine.

We describe a method for labeling chromosomal proteins with an amino-group-specific fluorescent reagent, fluorescamine. Chromosomes thus labeled appear either as uniformly fluorescent or as haloes in structure depending on the proteins remaining after treatment with acid-alcohol fixation. Using fluorescamine as a probe, we demonstrate that there is a substantial loss of labeled proteins during the chromosomal preparation and also during the trypsin treatment used in the banding of chromosomes.

Amnion↗

A high-resolution radiation hybrid map of chicken chromosome 5 and comparison with human chromosomes.

BACKGROUND: The resolution of radiation hybrid (RH) maps is intermediate between that of the genetic and BAC (Bacterial Artificial Chromosome) contig maps. Moreover, once framework RH maps of a genome have been constructed, a quick location of markers by simple PCR on the RH panel is possible. The chicken ChickRH6 panel recently produced was used here to construct a high resolution RH map of chicken GGA5. To confirm the validity of the map and to provide valuable comparative mapping information, both markers from the genetic map and a high number of ESTs (Expressed Sequence Tags) were used. Finally, this RH map was used for testing the accuracy of the chicken genome assembly for chromosome 5. RESULTS: A total of 169 markers (21 microsatellites and 148 ESTs) were typed on the ChickRH6 RH panel, of which 134 were assigned to GGA5. The final map is composed of 73 framework markers extending over a 1315.6 cR distance. The remaining 61 markers were placed alongside the framework markers within confidence intervals. CONCLUSION: The high resolution framework map obtained in this study has markers covering the entire chicken chromosome 5 and reveals the existence of a high number of rearrangements when compared to the human genome. Only two discrepancies were observed in relation to the sequence assembly recently reported for this chromosome.

Animals↗

A polymerase chain reaction-mediated yeast artificial chromosome-splitting technology for generating targeted yeast artificial chromosomes subclones.

The yeast artificial chromosomes (YAC) system makes it possible not only to clone large DNA fragments but also to simplify the physical mapping and functional analysis of chromosomes and genomes through YAC manipulation. To manipulate large DNA fragments cloned into YACs, YAC fragmentation has been developed and also a new method called the YAC-splitting method was developed recently. Although the YAC fragmentation method can be used to delete DNA from one side of a YAC, the YAC-splitting method generates two smaller YACs, both of which are transmitted to daughter cells during mitotic growth. This chapter describes the YAC-splitting method improved by incorporating polymerase chain reaction-mediated chromosome splitting (PCS) technique and by adding yeast autonomously replicating sequence (ARS) to the system. The PCS method combines a streamlined procedure (two-step PCR and one transformation per splitting event) with the Cre/loxP system for marker rescue. The improved YAC-splitting method can convert a targeted region of a eukaryotic chromosome within a YAC into a new replicating YAC.

Chromosomes, Artificial, Yeast↗

Genome-wide scan in a novel IgA nephropathy model identifies a susceptibility locus on murine chromosome 10, in a region syntenic to human IGAN1 on chromosome 6q22-23.

Genetic factors are considered to be involved in the initiation and progression of IgA nephropathy (IgAN) on the basis of racial differences in the prevalence and familial aggregation. The ddY mouse is a spontaneous animal model of human IgAN, with a highly variable incidence and extent of glomerular injury as a result of the heterogeneous background, resembling the human situation. It was hypothesized that susceptibility genes for IgAN can be detected by a genome-wide scan using this model. First, serial renal biopsies were performed at 20, 40, and 60 wk of age in 361 ddY mice. The ddY mice were classified into three groups on the basis of the onset of glomerular injury: Early onset at 20 wk (31.9%), late onset at 40 wk (37.9%), and quiescent even at 60 wk (30.2%). The severity of glomerular lesions in both onset groups correlated with the intensity of glomerular IgA deposition but not with serum IgA level. The genome-wide scan with 270 microsatellite markers identified three chromosomal regions on chromosomes 1, 9, and 10, which were significantly associated with the glomerular injuries. Surprisingly, the peak marker D10MIT86 on chromosome 10 is located on the region syntenic to human 6q22-23 with IGAN1, which is the responsible candidate of familial IgAN. In addition, D1MIT16 on chromosome 1 was very closely located at the locus of selectin gene, which is a known candidate of human IgAN. In conclusion, the three-group ddY mouse model can be a useful tool for identifying the susceptibility genes and also to examine their roles in the pathogenesis of IgAN.

Animals↗

An X-chromosome scan reveals a locus for fat distribution in chromosome region Xp21-22.

Several groups have completed autosomal genome scans for human obesity, but only two have examined the X chromosome. A French group reported linkage of BMI to Xp and Xq markers, and a Finnish group reported linkage of BMI to Xq. We scanned the X chromosome in two cohorts, 190 European-American families (940 members) and 43 African-American families (208 members). We examined five correlated obesity phenotypes, BMI, body fat percentage, hip and waist circumferences, and plasma leptin concentration. We also examined leptin resistance (leptin/BMI) and fat patterning (waist-to-hip ratio [WHR]). Variables were adjusted for age within generation, race, and sex. We genotyped 20 markers with average spacing of 10 cM and no interval >22 cM and conducted nonparametric analyses. Suggestive linkage was found for WHR only. Linkage was supported in both family sets, and support was especially strong for females. Z scores for analyses of female phenotypes were 2.69, 1.73, and 2.37 (P = 0.0036, 0.0418, and 0.0089) for African-Americans, European-Americans, and the combined sample, respectively. The peaks were 51-73 cM from the p terminus, 14-34 cM distal of the French report in Xp22. Our results suggest that a quantitative trait locus influencing fat distribution in women may lie in chromosome region Xp21-22; however, the linked interval is large and differs substantially from that of the French and Finnish groups. Given the positive but divergent results, it would be worthwhile for others to examine the X chromosome.

Adipose Tissue↗

Examination of candidate chromosomal regions for type 2 diabetes reveals a susceptibility locus on human chromosome 8p23.1.

In a panel of large Caucasian pedigrees, we genotyped markers in eight chromosomal regions previously reported as supporting linkage with type 2 diabetes. We previously reported significant linkage on chromosome 20q (maximum logarithm of odds score [MLS] = 2.79) in this panel. In the present analysis, candidate regions on 1q, 2q, 3q, 5q, 9q, and 10q yielded little evidence for linkage; a region on 2p (MLS = 1.64, P = 0.01 at position 9.0 cM) gave suggestive evidence of linkage; and a region on 8p (MLS = 3.67, P = 2.8 x 10(-5), at position 7.6 cM) gave significant evidence of linkage. Conditional analyses were performed for both 2p and 8p regions and the region reported on 20q. The MLS for 2p increased from 1.64 to 1.79 (empirical P = 0.142) when conditioned for heterogeneity on 20q. The case was similar for 8p, where the MLS increased from 3.67 to 4.51 (empirical P = 0.023) when conditioned on families without evidence of linkage at 20q. In conclusion, our data support a type 2 diabetes susceptibility locus on chromosome 8p that appears to be independent from other susceptibility loci. Although we were able to replicate linkage in our pedigrees on chromosome 2p, we did not find evidence of linkage for regions on 1q, 2q, 3q, 5q, 9q, or 10q.

Age of Onset↗

Structure of the human D1F15S1A locus: a chromosome 1 locus with 97% identity to the chromosome 3 gene coding for hepatocyte growth factor-like protein.

The human chromosome 3 locus coding for hepatocyte growth factor-like protein/macrophage stimulating protein (HGFL/MSP) is homologous to two sets of amplified loci on human chromosome 1 at 1p36. One copy of one of the amplified loci (D1F15S1A) has been further characterized by restriction enzyme and DNA sequence analysis. A total of 8331 bp of continuous sequence was determined for this locus. The first 6878 bp of sequence is 96.1% identical to the HGFL/MSP gene, while there is no homology between the two genes following nucleotide 6878. Based on the presence of a 5 bp deletion in putative exon 2 and several downstream stop codons it is very likely that this gene is a pseudogene. Screening of a human liver cDNA library with a chromosome 1-specific probe indicates that at least several other members of the chromosome 1 loci are transcribed.

Chromosomes, Human, Pair 1↗

Trisomy of the long arm of chromosome 1 resulting in a dicentric derivative (6)t(1;6) chromosome in a child with myelodysplastic syndrome following treatment for a primitive neuroectodermal tumor.

We report the clinical, hematologic, and cytogenetic findings for a child with secondary myelodysplastic syndrome (MDS) after treatment for a primitive neuroectodermal tumor. At the time of conversion to MDS, conventional cytogenetics revealed an unbalanced der(6)t(1;6) that resulted in trisomy of the long arm of chromosome 1 and partial monosomy and duplication of 6p. Using alpha satellite probes, fluorescence in situ hybridization of bone marrow cells showed that the rearranged chromosome contained the centromeres of both chromosomes 1 and 6, thus forming a dic(1;6) resulting in trisomy 1q. This report is the first to describe a case of childhood secondary myelodysplastic syndrome associated with a trisomy 1q involving chromosome 6.

Brain Neoplasms↗

Physical localization of single-copy sequences on pachytene chromosomes in maize (Zea mays L.) by chromosome in situ suppression hybridization.

A new approach for locating single-copy DNA sequences on pachytene chromosomes of maize (Zea mays L.) was developed. A cosmid clone with homologous sequences to a molecular marker (umc105a) linked to a quantitative trait locus (QTL) for resistance against sugarcane borer (SCB) was physically mapped by fluorescence in situ hybridization (FISH) to the short arm of chromosome 9. The marker umc105a was genetically placed in the centromeric region. To suppress signals generated by maize repetitive DNA, competitive in situ suppression (CISS) hybridization was necessary to obtain specific signals from umc105a. A centromere specific DNA probe (CentC) was used in a double-labeling technique as a reference marker. Fluorescence signals generated by umc105a cosmid and CentC were specific and highly reproducible. Thus the single-copy DNA sequence of umc105a was physically localized on the short arm of chromosome 9 near the telomere. This is the first report of physical localization of single-copy DNA sequence by CISS hybridization to a maize pachytene chromosome.

Chromosome Mapping↗

Definition of a small chromosomal rearrangement on chromosome 11p14 by molecular cytogenetics in situ hybridization.

Chromosomal in situ hybridization allows the detection and the definition of single copy DNA segments of very small size. In a particular case, we demonstrate the inactivity of this molecular cytogenetic technique. In this case, karyotype analysis revealed a chromosome 11p+. In situ hybridization of probes PBGD, D11S29, NCAM, and ETSI located at 11q23-qter shows that the extra chromosomal material on chromosome 11p+ is a duplication of the 11q23-qter region.

Abnormalities, Multiple↗

Localization of the photoreceptor gene ROM1 to human chromosome 11 and mouse chromosome 19: sublocalization to human 11q13 between PGA and PYGM.

Rom-1 is a retinal integral membrane protein that, together with the product of the human retinal degeneration slow gene (RDS), defines a photoreceptor-specific protein family. The gene for rom-1 (HGM symbol: ROM1) has been assigned to human chromosome 11 and mouse chromosome 19 by Southern blot analysis of somatic cell hybrid DNAs. ROM1 was regionally sublocalized to human 11p13-11q13 by using three mouse-human somatic cell hybrids; in situ hybridization refined the sublocalization to human 11q13. Analysis of somatic cell hybrids suggested that the most likely localization of ROM1 is in the approximately 2-cM interval between human PGA (human pepsinogen A) and PYGM (muscle glycogen phosphorylase). ROM1 appears to be a new member of a conserved syntenic group whose members include such genes as CD5, CD20, and OSBP (oxysterol-binding protein), on human chromosome 11 and mouse chromosome 19. Localization of the ROM1 gene will permit the examination of its linkage to hereditary retinopathies in man and mouse.

Animals↗

A novel human homeobox gene lies at the chromosome 10 breakpoint in lymphoid neoplasias with chromosomal translocation t(10;14).

The translocation t(10;14)(q24;q11) is an acquired change seen in 4% to 7% of T-cell acute lymphoblastic leukemias (T-ALL). We previously demonstrated that the translocation juxtaposes the T-cell receptor (TCR) delta-chain gene in chromosome 14q11 with a novel region in chromosome 10q24 and is likely catalyzed by recombinases normally involved in the generation of immunoglobulin and TCR diversity. We now present the sequence of a gene on chromosome 10 that lies immediately telomeric of the breakpoints in nine new ALL patients with acquired rearrangements in 10q24. The gene is a novel human homeobox gene and is expressed in leukemic cells from ALL patients with rearrangements in a defined chromosome 10 breakpoint cluster region, but not in other adult tissues or cell lines. This new gene has been designated HOX11. Our results strongly support a role for homeobox genes in oncogenesis and may represent the first example of a human cancer in which deregulated expression of an unaltered homeobox gene is involved in tumorigenesis.

Amino Acid Sequence↗

[X chromosome inactivation patterns in patients with Rett syndrome and their mothers and the parental origin of the priority inactive X chromosome].

OBJECTIVE: Rett syndrome (RTT) is a severe childhood neurodevelopmental disorder mainly affecting females. The pathogenic gene is located at Xq28, which codes for the methyl-CpG-binding protein 2. MECP2 gene is affected by X chromosome inactivation (XCI). The different XCI patterns of females could affect the expression ratios of pathogenic gene, causing changes in clinical symptoms. In order to understand the XCI patterns in RTT patients and the relationship between XCI pattern, genotype and phenotype, the XCI patterns in patients with RTT and their mothers, the parental origin of the priority inactive X chromosome in RTT, and the relations of XCI patterns with genotype and phenotype in RTT cases were analyzed. METHODS: Genomic DNA was extracted from peripheral blood of 55 cases with RTT (52 with MECP2 mutations, 3 without mutations), 53 mothers of RTT cases and 48 normal female controls. DNA was digested with methylation sensitive restriction endonuclease Hpa II. Then the undigested and digested DNAs were amplified via PCR for the first exon of human androgen receptor (AR) gene. PCR products were analyzed by Genescan. RESULTS: The heterozygotic rates of AR gene were 82%, 77% and 83% in RTT patients, mothers and controls, respectively. XCI distribution pattern of RTT was different from that of the mothers and control, P < 0.05. More mothers and controls than RTT patients were in the area of XCI 50:50 - 59:41. The differences between them were statistically significant (P < 0.05). No significant difference in XCI distribution patterns between mothers and the control groups was found (P > 0.05). Non-random XCI rates in the areas of XCI >or= 65:35 and >or= 80:20 were 53.35% and 17.8%, respectively, in RTT patients, compared with the mothers group (36.6%, 7.3%) and control group (35%, 10%), it was higher in RTT patients, but the difference was not statistically significant (P > 0.05). In 18 of 21 cases with XCI >or= 65:35, the priority inactive X chromosome was of paternal origin (85.7%). Variable XCI patterns were observed in the same gene mutation patients. The highly skewed XCI as well as the random XCI were found in patients with mild, severe and typical phenotype. The rate of highly skewed XCI in atypical patients was higher than that in typical RTT patients. The rate of highly skewed XCI in T158M was higher than the other type mutations. No highly skewed XCI was observed in cases with R133C mutation. CONCLUSION: The XCI distribution pattern of RTT patients was different from that of RTT mother and control groups. There was no significant difference in XCI distribution patterns between mothers and the control groups. It was not a main genetic pattern in RTT that mothers as the carriers to transmit the pathogenic gene to the patients. Non-random XCI was not the main XCI pattern in RTT patients. The priority inactive X chromosome was mainly of paternal origin. XCI could modify the clinical phenotype of RTT, but had limitations in explaining all the phenotypes manifested in RTT cases.

Adolescent↗

[Chromosomal localization of human X chromosome alphoid satellite DNA by in situ hybridization and its preliminary application].

In situ hybridization of human X chromosome-specific alphoid satellite DNA to human lymphocyte metaphase and interphase nuclei was carried out. The results showed that the probe hybridized with high specificity to the centromeric region at p11----q11 of the X chromosome. The number of silver grain clusters in the interphase nuclei was correlated with that of X chromosomes in the cells. 44% of the clusters were located near the nuclear membrane, the usual location of X chromatin (Barr body). The hybridized chromosomes were also R-banded with BrdU treatment, and the significance of this work was briefly discussed.

Centromere↗

[Relationship between group G chromosomes, especially chromosome 21, and the sensitivity of human cells to Coxsackie B viruses].

The R-method of differential chromosome staining by length was applied to comparative karyological studies on the culture of J 96 human cells susceptible to enteroviruses, and on the J 41 cell line derived from this culture and possessing high specific resistance to Coxsackie B viruses. Karyotype of the J 41 cell line was shown to be deprived of chromosome G21 (P less than 0.0001). The number of other chromosomes varied from cell to cell, but they are constantly present in the majority of cells of both the J 96 and J 41 cell lines. A conclusion is drawn that chromosome G21 incorporates gene(s) which controls the human cells susceptibility to Coxsackie B viruses.

Cell Line↗

Double insertion of homogeneously staining regions in chromosome 1 of wild Mus musculus musculus: effects on chromosome pairing and recombination.

An examination of the meiotic pattern of chromosome 1 isolated from a feral mouse population and containing a double insertion (Is) of homogeneously staining regions (HSRs) was carried out. The region delineated by the proximal breakpoint of Is(HSR;1C5) 1Icg and the distal breakpoint of Is(HSR;1E3)2Icg is desynapsed during the early pachytene stage and heterosynapsed at the midpachytene, as shown by electron microscopic analysis of synaptonemal complexes. The HSRs have no effect on the segregation of chromosome 1 in heterozygous mice. The lack of homosynapsis in the region under study causes chiasmata redistribution in heteromorphic bivalents. In normal males, single chiasmata are located in the medial part of the chromosome. In heterozygotes, this segment is heterosynapsed and unavailable for recombination. This leads to a significant decrease in the frequency of bivalents bearing single chiasmata. The total number of chiasmata per bivalent is much higher in heterozygous males than in normal ones. The recombination frequency between proximal markers fz and In also is higher in heterozygous animals. The increase in the total chiasma number in the heteromorphic bivalent is due to the addition of double chiasmata located mostly at precentromeric and pretelomeric regions of the chromosome.

Animals↗

Chromosome abnormalities in chronic myeloid leukaemia. A model for acquired chromosome changes in haematological malignancy.

The last decade has been very exciting for cancer cytogeneticists. At the start of the decade, the role of cytogenetics in clinical medicine was still unclear. Many felt that such investigations were largely of academic interest. Today, cytogenetic investigations are considered essential in many cancers, where they contribute in diagnosis, staging, choice of therapeutic protocol, and monitoring of the effects of therapy. The number of primary chromosome changes in human cancer exceeds 100, and while the majority of these changes are associated with haematological malignancies, the contribution from the solid tumours is now growing rapidly. Closer ties between scientists and physicians involved in laboratory and clinical medicine have resulted in the emergence of many well-defined cytogenetic-clinicopathological entities. With the advances in molecular biology that characterized the 1980s came the disappearance of all scepticism about the critical role played by chromosome change in oncogenesis. To date, we have learned more about the details of cancer biology in chronic myeloid leukaemia and the lymphoid malignancies through the molecular dissection of primary chromosome changes than through any other approach. Further studies will, no doubt, lead us to an understanding of the molecular basis of many of the primary and secondary chromosome changes that are non-randomly acquired in human cancer.

Chromosome Aberrations↗

Correlation of chromosome abnormalities with histologic and immunologic characteristics in non-Hodgkin's lymphoma and adult T cell leukemia-lymphoma. Fifth International Workshop on Chromosomes in Leukemia-Lymphoma.

To correlate cytogenetic findings with histology and immunophenotype, 260 newly diagnosed patients with non-Hodgkin's lymphoma (NHL) and 31 with adult T cell leukemia/lymphoma (ATL) were studied at the Fifth International Workshop on Chromosomes in Leukemia-Lymphoma. Clonal chromosome abnormalities were found in 85% of cases of NHL and in all cases of ATL. The most significant associations of histology with cytogenetics involved the 8q24 and 14;18 translocations. Of 23 NHL patients with an 8q24 translocation, 20 (87%) had small noncleaved cell (SNC) lymphoma. Of 57 NHL patients with a t(14;18)(q32;q21), 37 (65%) had a follicular lymphoma, and at least 13 others (23%) had a diffuse lymphoma of follicular center cell origin. Five others including two who also had an 8q24 translocation had SNC lymphoma; tumors in these patients lacked the monomorphic features seen in those with only an 8q24 translocation. The most striking associations of immunology with cytogenetics involved rearrangements of 14q11-13, abnormalities of 1p, trisomy 3, and trisomy 12. Abnormalities of 14q11-13 were correlated with T cell disease. Among 138 NHL and 24 ATL cases that lacked involvement of 8q24, t(14;18), or rearrangements of 14q11-13, abnormalities of 1p and trisomy 3 were significantly associated with the T cell phenotype (P less than .01) and trisomy 12 with the B cell phenotype (P less than .01). No karyotype difference was found between Japanese ATL and non-Japanese T cell lymphomas except that +3 occurred more often in the former (P = .06). Although the 8q24 translocations in 23 patients were distributed relatively equally among geographic regions (United States, ten; Europe, ten; Japan, three), the t(14;18) in 57 patients was much less frequently seen in Japan than in the other parts of the world (United States, 31; Europe, 21; Australia, four; Japan, one). Thirty-nine chromosome bands had breaks in five or more cases; a number of protooncogenes and genes related to lymphocyte function located in these bands are likely to be involved in the development of lymphoma. Thus, besides confirming the close association of particular chromosome abnormalities with histology, we have identified a number of new associations that merit molecular analysis.

Adolescent↗