Swimming navigation, open-field activity, and extrapolation behavior of two inbred mouse strains with Robertsonian translocation of chromosomes 8 and 17

Female mice from inbred strains carrying a Robertsonian translocation (nine CBARb and eight C57BL/6Rb) were compared with animals from their respective strains (seven CBA and nine C57BL/6) first in open-field activity (two exposures of 10-min duration), then during 5 days (with six trials each) in Morris' swimming navigation test, and finally, in their ability to extrapolate the future position of a food reward being moved slowly out of their reach. ANOVA (strain and translocation) revealed significant effects of Robertsonian translocations (Rb) in swimming navigation, Rb mice being impaired primarily in the initial phases of acquisition and during the first trials of platform reversal and the impairment being stronger in C57BL/6 mice. In the open field, Rb mice were as active as the normal strains but showed significantly increased path tortuosity and moved slightly faster. In the extrapolation task, Rb mice showed above-chance levels in moving to the target indicated by the disappearance of the stimulus, while normal mice chose at chance levels, but the translocation effects were not statistically significant. These data indicate that telocentric fusion of chromosomes may entail behavioral alterations, perhaps by subtle changes in neurotransmitters or limbic circuitry. The expression of such alterations, however, can be remarkably strain dependent.     

Oncogenesis in utero: fetal death due to acute myelogenous leukaemia with an MLL translocation

The incidence of translocations involving the 11q23 gene MLL is markedly increased in leukaemias that occur in infants <1 year of age. Epidemiological and molecular data have demonstrated that at least some of these translocations occur in utero. In this report we describe a case of fetal death at 36 weeks of gestation. At autopsy the fetus was found to have widely disseminated acute myelogenous leukaemia (AML), FAB subtype M5. Molecular cytogenetic studies of nuclei recovered from paraffin-embedded tissue sections demonstrated that the leukaemic cells contained an MLL translocation. This is the first detailed report, to our knowledge, of fetal death due to acute leukaemia, and directly demonstrates oncogenesis in utero.     

Robertsonian chromosomal rearrangements in the short-tailed shrew, Blarina carolinensis, in western Tennessee

We report significant heterozygosity for numerous Robertsonian translocations in the southern short-tailed shrew (Blarina carolinensis) in western Tennessee. Eight Robertsonian rearrangements were documented using G-banding techniques that explain the variability in diploid numbers from 46 throughout most of the range of the species to 34-40 in western Tennessee. These fusions resulted in the loss of telomere sequences and were not associated with nucleolar organizer regions. When heterozygocity is considered, the lowest diploid number possibly present would be 30. Four localities with distances of over 180 km apart were sampled, and 80-90% of the collected animals were heterozygous for at least one rearrangement. No putative parental type was found in western Tennessee. Heterozygosity for the same rearrangements was found in these different localities, and no monobrachial fusions were noted. Thus, this is a very wide hybrid zone with rare or absent parental types in the areas sampled or is an evolutionary stage preceding establishment of Robertsonian races. Selective forces, if any, were minimal, as evidenced by the wide area of polymorphism, significant heterozygosity, and the fact that the Robertsonian translocations were in Hardy-Weinberg equilibrium. The origin of such extensive polymorphism in western Tennessee is discussed, especially in light of putative effects of the New Madrid seismic activity. Similarities and differences are noted between the Blarina model and the well-documented variation in the European common shrew (Sorex araneus) and Mus musculus groups.     

Characterization of t(11;14) translocation in mantle cell lymphoma by fluorescent in situ hybridization

Characterization of chromosome abnormalities in leukemia and lymphoma have contributed to the understanding of the molecular basis of these neoplastic diseases. In addition, specific chromosomal aberrations have acquired diagnostic or prognostic value. The t(11;14)(q13;q32) chromosome translocation has been detected in mantle cell lymphomas. However, possibly due to the limits of conventional cytogenetic analysis and the presence of different breakpoints at the molecular level, it is possible that the true percentage of association is underestimated. In our study, we used a yeast artificial chromosome, spanning the entire area where the rearrangements occur on chromosome 11q13, to detect the presence of translocations by fluorescent in situ hybridization experiments. We detected BCL-1 translocations in eight of eight patients with clinical and immunological features of mantle cell lymphoma, suggesting that the t(11;14) translocation is a critical event in the pathogenesis of MCL and may be a primary element for the diagnosis. Since this translocation is associated with poor prognosis, its detection may help to make a correct diagnosis as well as to evaluate residual disease, which is critical to plan a rational chemotherapy regimen.     

Identification of new nonrandom translocations in multiple myeloma with multicolor spectral karyotyping

Multicolor spectral karyotyping (SKY) was performed on bone marrow samples from 50 patients with multiple myeloma (MM) in anticipation of discovering new previously unidentified translocations. All samples showed complex karyotypes with chromosome aberrations which, in most cases, were not fully characterized by G-banding. Patients of special interest were those who showed add(14)(q32), add(8)(q24) and those whose G-banding karyotypes showed poor chromosome morphology. Three new recurring chromosome translocations not previously reported in MM were identified. Two of the translocations involve recurring aberrations at band 14q32.3, the site of the IgH locus, with different exchange partners. The most frequently recurring rearrangement was a subtle translocation at 14q32.3 designated as a t(14;16)(q32;q22 approximately 23), which was identified in six patients. A second and larger translocation at 14q32, identified in two patients, was designated as a t(9;14)(p13;q32), previously associated with Waldenstrom's macroglobulinemia and lymphoplasmacytoid lymphoma. A third translocation, identified in two patients, involved a whole-arm t(6;8)(p10;q10) translocation. The SKY technique was able to refine the designations of over 156 aberrations not fully characterized by G-banding in this study and resolved additional chromosome aberrations in every patient studied except two. The t(14;16)(q32;q22 approximately 23) identified by SKY in this study suggests this may be a frequent translocation in MM associated with complex karyotypes and disease progression. Therefore, the SKY technique provides a useful adjunct to routine G-banding and fluorescence in situ hybridization studies in the cytogenetic analysis of MM.     

Structural abnormalities of the X chromosome in non-Hodgkin's lymphoma

It has recently been reported that additional X chromosomes occur in over 30% of B-cell non-Hodgkin's lymphomas (NHL), and that monosomy of the X chromosome occurs in 38% of female patients with T-cell leukaemia or lymphoma. These observations have suggested a possible role for the X chromosome in the evolution of NHL. We have now examined 280 cases of NHL, and have identified 19 examples of structurally altered X chromosomes in the malignant cells from 17 of these cases. These abnormalities were mainly characterized by either a translocation involving Xp22, or a translocation/deletion involving Xq28. The relevance of these observations is discussed with respect to other published reports, and together they suggest that lymphoma-associated oncogenes may exist on the X chromosome at bands p22 or q28.     

Recombination in a balanced complex translocation of a mother leading to a balanced reciprocal translocation in the child. Review of 60 cases of balanced complex translocations

We report an unusual case of a balanced reciprocal translocation with a recombinant chromosome which has arisen from a familial balanced complex translocation. Fluorescence in situ hybridization studies were essential for the identification of the breakpoints. A review of 60 cases of balanced complex translocations (BCT) has revealed three cases similar to ours. Carriers of BCT have a high risk of having spontaneous abortions or a child with an unbalanced karyotype. Certain types of balanced rearrangements involving an insertion can give rise to a simpler balanced translocation as a result of crossover. Our observations support the assumption that the chance that a de novo balanced complex translocation is associated with an abnormal phenotype increases with the number of breakpoints.     

A case of HTLV-I associated polyradiculoneuropathy and cerebral white matter lesions with smouldering type adult T cell leukemia

Chronic myelogenous leukemia (CML) is associated with an acquired karyotypic abnormality, the Philadelphia (Ph) chromosome, in 95% of cases. The Ph chromosome is the product of a balanced translocation that results in a hybrid gene that is considered essential for the pathogenesis of this disease. We have found a complex translocation involving chromosomes 9, 12, and 15 in a 42-year-old Haitian male with the clinical findings of CML. Complex translocations have been shown to result in the masking of the Ph chromosome. We used a mixture of two BCR-specific DNA probes for Southern blot analysis in order to test this hypothesis in our patient. High-molecular weight DNA was digested with the restriction enzymes BglII, BamHI and HindIII. The BglII digestion revealed the presence of two abnormal fragments of 3.9 and 3.0 kb and the BamHI digestion an abnormal 15-kb fragment. These data suggest there is a breakpoint in region 2 of M-bcr. The identification of this breakpoint confirms our hypothesis that a rearrangement involving 22q11 has occurred in the leukemic cells of our patient. A secondary translocation involving chromosomes 12 and 15 has hidden the effects of this translocation. Combined cytogenetic and molecular analysis establishes the karyotype of our patient as 46,XY,t(9;12;15;22)(q34;q12;q21;q11).     

The LMO1 and LDB1 proteins interact in human T cell acute leukaemia with the chromosomal translocation t(11;14)(p15;q11)

The ectopic expression of LMO1 or LMO2 in T cell acute leukaemias resulting from chromosomal translocations t(11;14)(p15;qll) or t(11;14)(p13;q11) respectively in a causal factor in tumorigenesis. LMO1 has been found as a heterodimer with a 46 Kd protein in a T cell line derived from a childhood T-acute leukaemia. This 46 Kd protein is the LIM-binding protein LDB1/NLI. The latter is a phosphoprotein and binds to LMO1 in its phosphorylated state and essentially all the LMO1 and LDB1 protein in the T cell line is part of the complex. Therefore, the LMO1-LDB1 interaction is likely to be involved in tumorigenesis after LMO1 is ectopically expressed following chromosomal translocation in T cells prior to development of acute leukaemias.     

Thyroid hemiagenesis

The translocation t(12;22)(p13;q11) has been consistently described in myeloid malignancies and shown to result from a fusion between the TEL and MN1 genes. Previously described deletions of 12p in acute lymphoblastic leukemias have been recently shown to harbor undetected translocations involving the TEL gene at 12p13. We document a case of an aggressive chronic B-cell leukemia whose cells had trisomy 12 and two unbalanced translocations involving 12p13, including a t(12;22)(p13;q11) as shown by conventional cytogenetics and fluorescence in situ hybridization (FISH). The 12p13 breakpoint of the t(12;22)(p13;q11) was telomeric to the TEL gene, and the second unbalanced translocation with breakpoint 12p13 resulted in the deletion of TEL. This case demonstrates that TEL gene deletions may be relevant in cases of mature B-lymphoproliferative diseases.     

Potential role for wild-type p53 in leukemias with MLL gene translocations

We used single-strand conformation polymorphism (SSCP) analysis of p53 exons 4-8 to screen for possible mutations in 25 pediatric de novo leukemias with translocations of the MLL gene at chromosome band 11q23. Of the 25 patients, 21 were infants. Fifteen cases were acute myeloid leukemia (AML), eight were acute lymphoblastic leukemia (ALL), and two cases were biphenotypic. Nineteen cases were studied at diagnosis and six at time of relapse. p53 mutations were absent in all 19 cases studied at the time of diagnosis. The only mutation was a TGC-->TTC transversion (cys-->phe) at codon 141 in exon 5 in a case of infant ALL at relapse that occurred by subclone evolution after MLL gene translocation. We previously showed that p53 mutations are also absent in pediatric treatment-related leukemias with MLL gene translocations. The absence of p53 mutations at initial transformation may suggest that the anti-apoptotic effect of mutant p53 is not important in leukemias with MLL gene translocations. Alternatively, exogenous DNA damage may be the common feature in treatment-related and de novo cases. Since MLL gene translocations may occur through DNA repair and wild-type p53 is central to DNA repair, the absence of p53 mutations raises the possibility that wild-type p53, not mutant p53, may be important in the genesis of leukemias with these translocations.     

Analysis of nonylphenol polyethoxylates and their degradation products in river water and sewage effluent by gas chromatography-ion trap (tandem) mass spectrometry with electron impact and chemical ionization

Two chromosome races of the house shrew Suncus murinus that differ from each other for five Robertsonian translocations (8.17, 9.13, 10.12, 11.16, and 14.15), heterochromatic insertions in chromosomes 7 and X, and multiple rearrangements in the Y chromosome were crossed and then intercrossed in captivity to produce a hybrid stock. Electron-microscopic analysis of synaptonemal complexes in fertile and sterile hybrid males was carried out. Meiosis in sterile males did not progress beyond pachytene and was severely disrupted. Meiotic arrest was not determined by structural heterozygosity: heterozygotes for all variant chromosomes distinguishing two parental races were found in both sterile and fertile male hybrids. Fertile hybrids demonstrated an orderly pairing of all chromosomes. In heterozygotes for Robertsonian fusions, completely paired trivalents were formed between the Robertsonian metacentrics and homologous acrocentrics. In heterozygotes for chromosome 7, bivalents with a small buckle were observed in a small fraction of pachytene cells. No differences were found in the morphology and pairing pattern of sex bivalents, composed of the X and Y chromosomes derived from the same or different parental races. Univalents, multivalents, and associations between X and Y chromosomes and autosomal trivalents, as well as associations of autosomal trivalents with each other, were observed in a small fraction of the pachytene cells of fertile males. Our results indicate that the system controlling male sterility in interracial hybrids of S. murinus is of genic rather than of chromosomal type.     

Molecular analysis to assign parental origin and distinguish de novo i(21q) from t(21q21q) in two Down syndrome fetuses

OBJECTIVE: We sought to determine the origin of two prenatal cases of chromosome 21 rearrangements not amenable to clarification by conventional cytogenetic methodology. METHODS: Hypervariable repeat polymorphisms (chromosome 21) were used to determine the type of structural rearrangement and the parental origin of the rearranged chromosome. The repeats used were highly polymorphic and located very close to the centromere; thus, the likelihood of differences among the parental alleles and overall informativeness were increased. RESULTS: The rea(21q21q) chromosomes were identified as a Robertsonian translocation in one fetus and an isochromosome in the other. The extra chromosome material was found to be maternal in origin in both cases. CONCLUSION: The ability to clarify the origin of abnormal chromosomal rearrangements provides valuable information concerning possible mechanisms of aneuploidy, as well as clinical data that may have an impact in assessing a patient's risk for abnormal offspring.     

Persistence of radiation-induced translocations in human peripheral blood determined by chromosome painting

We have investigated the persistence of translocations and other types of chromosome damage with time using human peripheral blood acutely exposed in vitro to 137Cs gamma rays at doses ranging from 0.5 to 4 Gy. Freshly drawn blood from one donor was irradiated and metaphase chromosomes were prepared 2 to 7 days after exposure. Chromosomes 1, 2 and 4 were painted red-orange and chromosomes 3, 5 and 6 were painted green by fluorescence in situ hybridization (FISH) using "semi-directly" labeled whole-chromosome painting probes. This type of labeling combines direct and indirect labeling and showed significant advantages over both these other methods. All types of structural chromosome aberrations were classified by the Protocol for Aberration Identification and Nomenclature Terminology (PAINT) system. The yields of dicentric chromosomes, acentric fragments and ring chromosomes diminished with time as expected. Translocations exhibited greater persistence but showed a clear and statistically significant reduction in frequency at all doses. The mathematical model suggested that the translocation frequencies would reach a plateau of approximately 4, 15, 51, 106 and 179 translocations per 100 cell equivalents after irradiation with 0.5, 1, 2, 3 and 4 Gy, respectively. When translocations were classified by the conventional system, an analysis of the distribution of translocations and dicentrics per cell indicated that both types of exchanges were Poisson-distributed 48 h postirradiation. However, cells bearing translocations have a higher possibility of having dicentrics than cells without translocations. These findings suggest that dicentrics may contribute to a decline of translocation frequencies with time, and that some translocations are not completely persistent. The results obtained here using human blood exposed in vitro may influence the use of translocations as a retrospective biodosimeter of exposure to ionizing radiation in humans.     

Gender distinctions and lateral asymmetry in the low-level auditory brainstem response of the human neonate

Given the reported long-range cis-inactivating effect of the XIST gene in early embryonic development and the lack of requirement of X-chromosome-specific elements for propagating the inactive state, there exists the possibility of cis inactivation of autosomal material after de novo translocation to an inactive X chromosome (Xi) in differentiated cells. We have analyzed de novo radiation-induced translocations between the Xi and autosomes to study the maintenance and spreading of X-chromosome inactivation (X inactivation) in relation to the position of the X-inactivation center (XIC)/XIST in differentiated cells. Autosome/Xi translocations were detected by fluorescence in situ hybridization (FISH). The activation status of the chromosomes involved in the translocation was determined by simultaneous immunocytogenetic studies using antibodies against either BrdU incorporated at late S phase or acetylated histone H4. The position of XIC/XIST in the reciprocal products of the translocation was determined by XIST-specific FISH and computer enhancement. In other experiments, the Xq13 region carrying XIC/XIST was localized by computer enhancement of the DAPI banding pattern. Our study in differentiated cells provides a visual demonstration that physical separation from XIC/XIST does not result in reactivation of inactive X-chromosome material and that X inactivation is not spread to the translocated autosomes irrespective of the position of XIC/XIST. This observation suggests that physical linkage to XIC/XIST does not lead to de novo inactivation of autosomal material.     

Analysis of 1;17 translocation breakpoints in neuroblastoma: implications for mapping of neuroblastoma genes

Deletions and translocations resulting in loss of distal 1p-material are known to occur frequently in advanced neuroblastomas. Fluorescence in situ hybridisation (FISH) showed that 17q was most frequently involved in chromosome 1p translocations. A review of the literature shows that 10 of 27 cell lines carry 1;17 translocations. Similar translocations were also observed in primary tumours. Together with the occurrence of a constitutional 1;17 translocation in a neuroblastoma patient, these observations suggest a particular role for these chromosome re-arrangements in the development of neuroblastoma. Apart from the loss of distal 1p-material, these translocations invariably lead to extra copies of 17q. This also suggested a possible role for genes on 17q in neuroblastoma tumorigenesis. Further support for this hypothesis comes from the observation that in those cell lines without 1;17 translocations, other chromosome 17q translocations were present. These too lead to extra chromosome 17q material. Molecular analysis of 1;17 translocation breakpoints revealed breakpoint heterogeneity both on 1p and 17q, which suggests the involvement of more than 2 single genes on 1p and 17q. The localisation of the different 1p-breakpoints occurring in 1;17 translocations in neuroblastoma are discussed with respect to the recently identified candidate tumor suppressor regions and genes on 1p. In this study, we focused on the molecular analysis of the 17q breakpoints in 1;17 translocations. Detailed physical mapping of the constitutional 17q breakpoint allowed for the construction of a YAC contig covering the breakpoint. Furthermore, a refined position was determined for a number of 17q breakpoints of 1;17 translocations found in neuroblastoma cell lines. The most distal 17q breakpoint was identified in cell line UHG-NP and mapped telomeric to cosmid cCI17-1049 (17q21). This suggests that genes involved in a dosage-dependent manner in the development of neuroblastoma map in the distal segment 17q22-qter. Future studies aim at the molecular cloning of 1;17 translocation breakpoints and at deciphering the mechanisms leading to 1;17 translocations and possibly to the identification of neuroblastoma genes at or in the vicinity of these breakpoints.     

多发性骨髓瘤中14q32易位与13q14缺失的相关性研究

目的 研究多发性骨髓瘤(MM)常见的分子遗传学异常14q32易位与13q14缺失及其与临床指标的关系.方法 采用间期荧光原位杂交(I-FISH)技术应用RB1、D13S319和LSI IGHC/IGHV探针检测49例MM患者骨髓标本中RB1基因、13q14.3缺失及14q32易位,结合临床资料作统计分析.结果 49例MM患者有26例(53.1%)检测到14q32易位,25例(51.02%)存在13q14缺失(其中18例检测到13q14.3缺失,9例存在RB1缺失).Spearman相关分析显示,14q32易位多见于浆细胞比例高的患者(r=0.316,P=0.27),与患者年龄、国际分期系统(ISS)分期、免疫球蛋白分型、β2微球蛋白及肾损害无相关性(P＞0.05).结论 13q14缺失及14q32相关的易位在MM中发生率均较高,两者有密切相关性;14q32易位的MM患者浆细胞百分比明显升高,14q32易位的检测可作为预测MM预后的指标.     

Developmental and endocrine aspects of normal ovarian aging

The fluorescence plus Giemsa (FPG) and fluorescence in situ hybridization (FISH) techniques have been used to determine, respectively, the frequencies of sister chromatid exchanges (SCEs) and stable chromosome aberrations (translocations) induced by different concentrations of BrdU in the Chinese hamster ovary cell mutant EM9 and its parental line AA8. The results indicate that BrdU induced a high frequency of SCEs and translocations in EM9 as compared with AA8, and that the translocation/dicentric ratio was also higher in the mutant cell line than in the parental cell line in both untreated and BrdU-treated cultures. These observations may indicate a possible relationship between the molecular mechanisms involved in the formation of SCEs and translocations.