Karyotype analysis of 161 unrelated schizophrenics: no increased rates of X chromosome mosaicism or inv(9), using ethnically matched and age-stratified controls.

Chromosomal aberrations have long been studied in an effort to identify susceptibility genes in schizophrenia. The two most frequently detected abnormalities are X chromosome mosaicism in female patients and pericentric inversions of chromosome 9 [inv(9)]. Chromosome X aneuploidies are known to be age dependent but differences due to ethnicity remain undetermined. In the case of inv(9), its prevalence in the general population varies with ethnicity. To evaluate the importance of these karyotypic changes in schizophrenia, cytogenetic analysis was performed on 161 unrelated schizophrenics of Japanese origin. We observed an increase in the incidence of X chromosome mosaicism in female schizophrenics with age. However, when compared with age matched female controls (92 individuals), no significant differences between patient and control samples were detected. Moreover, this study showed that there is no significant difference in the incidence of X chromosome loss between Japanese and Caucasian populations. The four cases with inv(9) (2.5%) detected in this study, did not differ significantly from the reported incidence of between 1.7 and 2.1% seen in the general Japanese population. We also observed a small number of additional karyotypic changes, none of which were recurrent. This is the first report to examine the comparative rates of X mosaicism in female schizophrenics and age matched controls.

The cloning, mapping and expression of a novel gene, BRL, related to the AF10 leukaemia gene.

The MLL gene is reciprocally translocated with one of a number of different partner genes in a proportion of human acute leukaemias. The precise mechanism of oncogenic transformation is unclear since most of the partner genes encode unrelated proteins. However, two partner genes, AF10 and AF17 are related through the presence of a cysteine rich region and a leucine zipper. The identification of other proteins with these structures will aid our understanding of their role in normal and leukaemic cells. We report the cloning of a novel human gene (BRL) which encodes a protein containing a cysteine rich region related to that of AF10 and AF17 and is overall most closely related to the previously known protein BR140. BRL maps to chromosome 22q13 and shows high levels of expression in testis and several cell lines. The deduced protein sequence also contains a bromodomain, four potential LXXLL motifs and four predicted nuclear localization signals. A monoclonal antibody raised to a BRL peptide sequence confirmed its widespread expression as a 120 Kd protein and demonstrated localization to the nucleus within spermatocytes.

Molecular analysis of an unstable genomic region at chromosome band 11q23 reveals a disruption of the gene encoding the alpha2 subunit of platelet-activating factor acetylhydrolase (Pafah1a2) in human lymphoma.

A region of 150 kb has been analysed around a previously isolated, lymphoma associated, translocation breakpoint located at chromosome band 11q23. This balanced and reciprocal translocation, t(11;14)(q32;q23), has been shown to result in the fusion between chromosome 11 specific sequence and the switch gamma4 region of the IGH locus. The LPC gene, encoding a novel proprotein convertase belonging to the furin family, has been identified in this region. In order to characterize further the region surrounding the translocation, we have determined the detailed structure of LPC. Here we show that LPC consists of at least 16 exons covering 25 kb, and that there is a partial duplication, involving mobile genetic elements and containing LPC exons 13-17 in a tail-tail configuration at 65 kb downstream. Since the chromosomal breakpoint lay between these two structures, the intervening region was further analysed and shown to contain at least two unrelated genes. The previously known SM22 gene was localized close to the 3' tail of LPC. Furthermore, we identified the gene encoding the alpha2 subunit of platelet-activating factor acetylhydrolase (Pafah1a2) at the chromosomal breakpoint. The position of another previously identified breakpoint was also located to within the first intron of this gene. Altogether, our results give evidence of a genomic instability of this area of 11q23 and show that Pafah1a2 and not LPC is the gene disrupted by the translocation, suggesting that deregulated Pafah1a2 may have a role in lymphomagenesis.

Gene BR140, which is related to AF10 and AF17, maps to chromosome band 3p25.

The genes AF10 and AF17 have been identified as the basis of the t(10;11) and t(11;17) translocations, events that result in their fusion to the MLL/HRX gene in acute myeloid leukaemias. AF10 and AF17 bear significant homology to each other within their putative zinc finger and leucine zipper domains, although they are diverged outside these regions. The BR140 gene encodes a 140 kDa protein of unknown function that contains a putative zinc finger domain, a leucine zipper region, and, in addition, a bromo domain. The zinc finger and leucine zipper domains of BR140 have significant homology to those of AF10 and AF17, suggesting that it belongs to this newly described gene family and, therefore, could be a target for chromosome translocation. To assess the potential involvement of BR140 in chromosome translocations in leukaemia, the chromosomal location of the BR140 gene has been determined by using several independent methods. A combination of Southern analysis, polymerase chain reactions (PCR) on monochromosomal cell hybrids, and fluorescence in situ hybridisation (FISH) has been used to show that the BR140 gene maps to chromosome band 3p25.

A new member of the proprotein convertase gene family (LPC) is located at a chromosome translocation breakpoint in lymphomas.

A new member of the proprotein convertase gene family (LPC) has been identified at a chromosome translocation breakpoint occurring in a high grade lymphoma. The translocation t(11;14)(q23;q32) has been molecularly cloned and shown to be the result of a fusion between an intron in the 3' -untranslated region of LPC with a sequence close to the switch region S gamma 4 of the IGH locus. The LPC gene encodes a protein of 785 amino acids with substantial homology to furin and the other members of the proprotein convertase family and represents a novel target for chromosome translocation and subsequent deregulation.

Detection of cells bearing the t(14;18) translocation following myeloablative treatment and autologous bone marrow transplantation for follicular lymphoma.

PURPOSE: To use the polymerase chain reaction (PCR) technique for molecular assessment of the results of myeloablative treatment of follicular lymphoma with autologous bone marrow transplantation. PATIENTS AND METHODS: Seventy-six patients with follicular or transformed follicular lymphoma were treated with cyclophosphamide 60 mg/kg x 2 and total-body irradiation 12 Gy, supported by autologous bone marrow transplantation. The bone marrow mononuclear cell fraction was treated in vitro with CD20 monoclonal antibody and baby rabbit complement. The PCR technique was used to identify 50 patients with amplifiable t(14; 18) translocations in biopsy material from lymph nodes or bone marrow infiltrated by lymphoma. RESULTS: Following treatment of the harvested bone marrow in vitro, 29 samples were tested by PCR to assess the efficacy of purging. In 25 cases, the same t(14; 18) sequences were amplified as from the patients' original biopsies, while in four cases, the marrow became PCR-negative. Three of the four patients treated with PCR-negative marrow subsequently developed recurrent lymphoma, compared with 11 of 25 in the PCR-positive group. Bone marrow and peripheral-blood mononuclear cell samples from 27 patients were studied during the follow-up period. All but one had the presence of the lymphoma-related t(14; 18) clone detectable by PCR and confirmed by direct sequencing from at least one sample between 3 months and 7 years after reinfusion of the bone marrow. With a median follow-up duration of 3 years, 13 patients developed recurrent disease, 13 remained in remission with the t(14; 18) still detectable, and one died of acute myeloid leukemia. CONCLUSION: This form of therapy does not eliminate the lymphoma-related t(14; 18)-bearing clone of cells, although the significance of its continued presence is uncertain. Improved methods for both treatment of the bone marrow in vitro and treatment of the lymphoma in vivo are required.

Molecular cloning of a novel 11q23 breakpoint associated with non-Hodgkin's lymphoma.

Chromosomal analysis of a non-Hodgkin's lymphoma revealed a t(11;14)(q23;q32) translocation amongst other abnormalities. To investigate the molecular basis of this translocation, a cosmid library was constructed from the tumour DNA and the rearranged IGH locus was isolated in a single cosmid. Fluorescence in situ hybridization confirmed that the cloned region contained sequences from chromosome 11q23 fused to chromosome 14q32. Sequence analysis identified the breakpoint as a fusion between a region from the switch segment of the C gamma 4 gene of the IGH locus and an unknown sequence on chromosome 11. The chromosome 11 sequence maps proximal to the CD3 gene cluster and is therefore distinct from both the HTRX1 gene (rearranged in acute leukaemias) and the RCK gene (rearranged in a cell line derived from a histiocytic B-cell lymphoma). This newly identified region contains a cluster of rare cutting restriction enzyme sites located within 200 bases of the breakpoint, suggestive of a CpG island. Although this t(11;14)(q23;q32) translocation and that in the RC-K8 cell line affect different regions on chromosome 11, the breakpoints on chromosome 14 were found to have occurred at equivalent positions of S gamma 2 and S gamma 4 segments.

Analysis of differentially expressed genes in retinitis pigmentosa retinas. Altered expression of clusterin mRNA.

The molecular and cellular processes underlying photoreceptor degeneration in retinitis pigmentosa (RP) are unknown. We have investigated gene expression in diseased retinas using differential hybridization screening of a retinal cDNA library with probes derived from normal and RP retinal RNA. Most differential clones detected corresponded to transcripts absent from the dystrophic state, including e.g. opsin. However, one clone was noticeably increased in RP in comparison with the control: partial sequencing showed it encoded clusterin. Increased expression of clusterin has been identified in several cases of tissues undergoing apoptosis (programmed cell death), and our finding suggests that the degenerative changes in advanced RP may represent another example of apoptosis, possibly with common causative mechanisms.

The significance of circulating cells carrying t(14;18) in long remission from follicular lymphoma.

Peripheral blood mononuclear cell fractions from 15 patients in continuous clinical remission from follicular lymphoma for longer than 10 years were examined for cells carrying the t(14;18) translocation using the polymerase chain reaction (PCR). The assay used was able to detect one positive cell in approximately 5 x 10(5) cells (a single 14q+ molecule in 2.5 micrograms DNA). Cells positive for t(14;18) were found in six of eight patients initially presenting with stage III or IV disease, compared with zero of seven of those with stage I or II disease (P less than .05). In two cases 14q+ junction regions were also successfully amplified from formalin-fixed biopsy material obtained at presentation 12 and 17 years previously. In both, sequence analysis demonstrated that the cells circulating in remission belonged to the original clone. These results indicate that cells bearing t(14;18) frequently persist in the peripheral blood in long remission of advanced follicular lymphoma and question the value of their presence as a predictor of relapse.

A new non-Hodgkin's B-cell line (DoHH2) with a chromosomal translocation t(14;18)(q32;q21).

A spontaneously growing EBV-negative B-cell line (DoHH2) was established from the pleural fluid cells of a 60-year-old man with centroblastic/centrocytic non-Hodgkin's lymphoma, that had transformed into an immunoblastic lymphoma. The pleural fluid cells and the DoHH2 cells expressed IgG lambda, were reactive with CD10 and CD19 monoclonal antibodies, and showed by cytogenetic analysis 48,XY, +7, +del(12)(q24), t(14;18)(q32;q21). Southern blot analysis of mini-satellite DNA patterns, and of rearrangements of the immunoglobulin genes and bcl-2, confirmed that the cell line was derived from the patient's clonal lymphoma cells. Direct nucleotide sequence analysis on polymerase chain reaction (PCR) products of the t(14;18) junction revealed an identical sequence for the JH-bcl-2 junction at JH6 and in the major breakpoint region of bcl-2 in both the original tumor cells and the DoHH2 cell line. The cell line was valuable as a standard quantification control for PCR analysis of the t(14;18) breakpoint. Titration experiments demonstrated the detection of up to one tumor cell in 10(5) normal blood lymphocytes.

Direct sequence analysis of 14q+ and 18q- chromosome junctions at the MBR and MCR revealing clustering within the MBR in follicular lymphoma.

The t(14;18) translocation is a highly consistent feature of follicular lymphoma although the underlying mechanism generating this fusion remains uncertain. The breakpoints on chromosome 18 are at one of two sites, designated mbr and mcr, in the bcl-2 gene. A polymerase chain reaction strategy has been developed for amplification and direct sequencing of the resultant 14q+ and 18q- reciprocal junctions. Sequence analysis of the amplified 14q+ junction established that 21 tumours contained a bcl-2 (mbr) sequence to an immunoglobulin JH region, the majority being J5 or J6. A nonrandom pattern of breakpoints within the mbr region was found. Clustering of the breakpoint occurred with over 60% of the translocations clustering within 10 bases. There was a second cluster within the mbr 50 bases 3' of the first cluster. One of these junctions had an unusual configuration with the bcl-2 and JH sequences separated by a recognisable DH region. This suggests that at least some of the junctional sequences, previously thought of as N insertions, may be fragments of unrecognised DH regions. In one of these tumours it was possible to sequence the reciprocal 18q- junction, showing it to consist of a DH/bcl-2 (mbr) fusion. Analysis of both reciprocal junctions for a translocation in the mcr region of bcl-2, showed that this 18q- junction also consisted of DH fused to a bcl-2 sequence. In contrast to previous analyses, which demonstrated either loss or duplication of bcl-2 sequences at the breakpoints, the bcl-2 sequence was conserved during the mbr and mcr translocations in this study.(ABSTRACT TRUNCATED AT 250 WORDS)