[Structure, use, and risks of biomaterial repositories of embryonal tumors]

Availability of statistically sufficient numbers of tumor samples and other biomaterials in high quality together with corresponding clinical data is crucial for biomedical research. Tumor repositories from individual scientists are mostly not sufficient to satisfy these criteria, especially since pediatric tumors are rare. In 2000 three centralized tumor repositories (neuroblastoma in Cologne, nephroblastoma in Würzburg, hepatoblastoma, brain tumors in Bonn) have been established by the "German Competence Net Pediatric Oncology und Hematology". The aim was to collect biomaterial including tumor samples, normal tissue, and blood in high quality for research and diagnostic purposes at a central institution. Informed consent of the parents or patients is a prerequisite for scientific use of the samples and is requested by the therapy trial. The samples are collected according to accepted standards and shipped in the specially designed Tumorbox. The tumor repository organizes the distribution of the samples to the cooperating diagnostic laboratories. The number of collected tumor samples has increased over the years. In 2000, samples from 200 patients were collected while the patient number increased to 321 in 2005. Over the years the tumor repositories collected more than 7,150 samples (fresh frozen tumor, fresh frozen normal tissue, and blood). Through links with clinical trial databases the samples can be connected with clinical data. 12 of 14 applications for tumor material to be used in specific scientific projects have been approved by an independent supervisory board. The establishment of central tumor repositories represents a major step for biomedical research activities and quality control in pediatric oncology.

Expression profiling of Wilms tumors reveals new candidate genes for different clinical parameters

Wilms tumor is the most frequent renal neoplasm in children, but our understanding of its genetic basis is still limited. We performed cDNA microarray experiments using 63 primary Wilms tumors with the aim of detecting new candidate genes associated with malignancy grade and tumor progression. All tumors had received preoperative chemotherapy as mandated by the SIOP protocol, which sets this study apart from related approaches in the Unites States that are based on untreated samples. The stratification of expression data according to clinical criteria allowed a rather clear distinction between different subsets of Wilms tumors. Clear-cut differences in expression patterns were discovered between relapse-free as opposed to relapsed tumors and tumors with intermediate risk as opposed to high risk histology. Several differentially expressed genes, e.g.TRIM22, CENPF, MYCN, CTGF, RARRES3 and EZH2, were associated with Wilms tumor progression. For a subset of differentially expressed genes, microarray data were confirmed by real-time RT-PCR on the original set of tumors. Interestingly, we found the retinoic acid pathway to be deregulated at different levels in advanced tumors suggesting that treatment of these tumors with retinoic acid may represent a promising novel therapeutic approach.

Botulinumtoxin�A in der orthop�dischen Schmerztherapie

Botulinum toxin A (BTX A) has been used for more than 20 years as a safe and effective treatment for numerous diseases characterized by pathological muscle hypertension. In patients suffering from dystonia or spasticity, it has been observed that use of BTX A results not only in muscle relaxation but also frequently relieves associated pain. This pain relief is often seen earlier and to a much greater extent than the muscular relaxation itself. This has led to extending the use of BTX A to treat various focal pain syndromes. The results of initial studies in specific musculoskeletal pain therapy suggest that BTX A infiltrations are effective in the treatment of chronic, therapy-resistant pain of the shoulder and back region. Furthermore, BTX A has been found to be a less invasive option for the treatment of chronic epicondylitis and similar tendonitis conditions. The healing process following rupture of tendons or muscle transfer operations may be improved. In adults with increased muscle tone and endoprostheses, the targeted relaxation of spastic muscles might increase the lifetime of the implant and diminish aseptic loosening. In children with cerebral palsy, prophylactic treatment of hip luxation appears possible. The doses used in pain therapy are low; if correctly applied, the tolerance and safety are high and the effect lasts for a number of weeks.

A murine model of Holt-Oram syndrome defines roles of the T-box transcription factor Tbx5 in cardiogenesis and disease

Heterozygous Tbx5(del/+) mice were generated to study the mechanisms by which TBX5 haploinsufficiency causes cardiac and forelimb abnormalities seen in Holt-Oram syndrome. Tbx5 deficiency in homozygous mice (Tbx5(del/del)) decreased expression of multiple genes and caused severe hypoplasia of posterior domains in the developing heart. Surprisingly, Tbx5 haploinsufficiency also markedly decreased atrial natriuretic factor (ANF) and connexin 40 (cx40) transcription, implicating these as Tbx5 target genes and providing a mechanism by which 50% reduction of T-box transcription factors cause disease. Direct and cooperative transactivation of the ANF and cx40 promoters by Tbx5 and the homeodomain transcription factor Nkx2-5 was also demonstrated. These studies provide one potential explanation for Holt-Oram syndrome conduction system defects, suggest mechanisms for intrafamilial phenotypic variability, and account for related cardiac malformations caused by other transcription factor mutations.

Gain of 1q is associated with adverse outcome in favorable histology Wilms' tumors

Although several genes/genetic loci involved in the etiology of Wilms' tumor have been identified, little is known of the molecular changes associated with relapse. We therefore undertook an analysis by comparative genomic hybridization (CGH) of 58 tumor samples of favorable histology Wilms' tumor taken at initial diagnosis and/or relapse. Tumors with anaplastic histology were excluded as this is known to be associated with p53 mutation and a poor prognosis. A control group of 21 Wilms' tumors that did not relapse was also analyzed. The overall frequency of gains or losses of genetic material detected by CGH was similar in both groups (77% in relapsing tumors and 70% in the nonrelapse group) as was the median number of changes per tumor (relapse group: n = 4, range, 1 to 19; nonrelapse group: n = 3, range, 1 to 8). However, gain of 1q was significantly more frequent in the relapse series [27 of 46 (59%) versus 5 of 21 (24%), P: = 0.019]. In 12 matched tumor pairs, the CGH profiles, including 1q gain, were similar at diagnosis and relapse, with little evidence for further copy number changes being involved in clonal evolution. The results suggest that 1q gain at diagnosis could be used to identify patients with favorable histology Wilms' tumor at increased risk of relapse who might benefit from early treatment intensification.

Analysis of HeyL expression in wild-type and Notch pathway mutant mouse embryos

In vertebrates Notch signaling regulates cell fate decisions and boundary formation and it underlies several murine and human diseases. Gene targeting experiments point to key roles of Notch receptors, ligands, modulators and downstream targets in somitogenesis, neurogenesis and vascular development. Here we report the embryonic expression of the hairy-related basic helix-loop-helix gene HeyL in wild-type and Notch pathway mutant mice. We show that HeyL is strongly expressed in the presomitic mesoderm, the somites, the peripheral nervous system and smooth muscle of all arteries. Loss of HeyL expression at the level of nascent somites in Notch1 and Delta-like1 knockout mutants implicates HeyL as a Notch effector during somite formation. Furthermore, HeyL expression in vascular smooth muscle cells and in the thymus strikingly overlaps with that of Notch3, mutations of which underlie the CADASIL vascular disorder.

Oscillating expression of c-Hey2 in the presomitic mesoderm suggests that the segmentation clock may use combinatorial signaling through multiple interacting bHLH factors

Vertebrate somitogenesis comprises the generation of a temporal periodicity, the establishment of anteroposterior compartment identity, and the translation of the temporal periodicity into the metameric pattern of somites. Molecular players at each of these steps are beginning to be identified. Especially, members of the Notch signaling cascade appear to be involved in setting up the somitogenesis clock and subsequent events. We had previously demonstrated specific expression of the mHey1 and mHey2 basic helix-loop-helix (bHLH) factors during somitogenesis. Here we show that perturbed Notch signaling in Dll1 and Notch1 knockout mutants affects this expression in the presomitic mesoderm (PSM) and the somites. In the caudal PSM, however, mHey2 expression is maintained and thus is likely to be independent of Notch signaling. Furthermore, we analysed the dynamic expression of the respective chicken c-Hey1 and c-Hey2 genes during somitogenesis. Not only is c-Hey2 rhythmically expressed across the chicken presomitic mesoderm like c-hairy1, but its transcription is similarly independent of de novo protein synthesis. In contrast, the dynamic expression of c-Hey1 is restricted to the anterior segmental plate. Both c-Hey genes are coexpressed with c-hairy1 in the posterior somite half. Further in vitro and in vivo interaction assays demonstrated direct homo- and heterodimerisation between these hairy-related bHLH proteins, suggesting a combinatorial action in both the generation of a temporal periodicity and the anterior-posterior somite compartmentalisation.

Comparative analysis of the human and mouse Hey1 promoter: Hey genes are new Notch target genes

Hey genes (Hey1, Hey2 and HeyL) encode a new group of basic helix-loop-helix transcription factors that are related to the hairy/Enhancer of split genes. In the present study, we cloned and characterized the promoter region of the human and mouse Hey1 gene. The transcription initiation site was located 138 nucleotides upstream of the start codon. There is a minimal sequence element (nt -30 to -247) that is essential and important for basal transcription in three different cell types. Further upstream, a highly conserved sequence block (nt -324 to -646; approximately 90% human/mouse similarity) could be identified that contains several putative binding sites for transcription factors and likely represents an important regulatory region for this gene. Cotransfection experiments demonstrated that the mHey1 promoter activity is up-regulated by the activated form of all four mammalian Notch receptors via two functional RBP-Jkappa binding sites. The other members of the Hey gene family, Hey2 and HeyL, also possess RBP-Jkappa binding sites and they are similarly responsive to Notch signaling. Thus, our data clearly demonstrate that Hey genes form a new class of Notch signal transducers that should prove to be relevant in various developmental processes.

Screen for genes regulated during early kidney morphogenesis

Kidney development starts with the reciprocal induction of mesenchymal and ureteric bud cells which leads to condensation, epithelialization, and nephron formation in the mesenchyme. To identify changes in gene expression during these processes, we compared differential display polymerase chain reaction (PCR) profiles of uninduced and induced mesenchymal cells. In vitro kidney development in the form of the transfilter organ culture system was used to generate homogeneous cell populations for this type of comparison. Here we describe the isolation of known and novel genetags from this screening. Among the known genes the ufo receptor tyrosine kinase, sFRP2, and the groucho related gene (grg) were verified as being upregulated upon induction. With four of eight novel genes tested, Northern blot analysis proved to be sensitive enough to confirm differential expression. To improve sensitivity and gain additional spatial information, in situ hybridization was performed. Expression analysis of two differential display PCR products, designated C0-5 and M2-4, demonstrated the cell-specific and dynamic expression of these novel genetags in the developing kidney and other tissues. C0-5 transcripts were expressed in the ureteric bud, S-shaped bodies, and in the collecting system. Signals for M2-4, a gene not detectable by Northern blot analysis, were only found in condensing mesenchymal cells and early differentiation stages, but not in the collecting ducts. The large fraction of novel genetags from the present screening that have not yet been analyzed provides a rich resource to clone genetic networks regulating early nephrogenesis.

Characterization of the human and mouse HEY1, HEY2, and HEYL genes: cloning, mapping, and mutation screening of a new bHLH gene family

Many basic helix-loop-helix (bHLH) transcription factors are known as key regulators of embryonic development or differentiation in various species. We have isolated and characterized three new hairy-related bHLH transcription factor genes from mouse and human (hairy and Enhancer-of-split related with YRPW motif; HEY1, HEY2, and HEYL). All three HEY genes have a similar genomic structure with five exons. Together with a highly related Drosophila homologue, they form a new bHLH gene subfamily that is different from both hairy and the known vertebrate Hes and Her genes. While the overall structure with the bHLH domain, Orange domain, and WRPW motif is similar, the last motif is changed to KPYRPWG in Hey1/2 and absent in HeyL. This and other sequence features suggest Hey proteins to have unique functional properties. The genes were mapped by fluorescence in situ hybridization and RH mapping to the following human chromosomes: (HEY1) 8q21, (HEY2) 6q21, and (HEYL) 1p34.3. Based on expression patterns and map location, HEY genes are candidates for several human or mouse disease loci. However, initial screening of DNA from affected individuals for two human disorders and four mouse mutants did not reveal any diagnostic alterations in the coding regions.

Molecular analysis of E-cadherin and cadherin-11 in Wilms' tumours

Different studies of Wilms' tumours have demonstrated a loss of heterozygosity (LOH) of chromosome 16q ranging from 17 to 25%. In order to search for a potential tumour suppressor gene on 16q, we chose the calcium-dependent cell adhesion molecules E-cadherin and cadherin-11 as candidate genes, which are both located on the long arm of chromosome 16. E-cadherin is known to be expressed in epithelial structures, whereas cadherin-11 is supposed to be expressed in mesenchymal structures and developing epithelium, including renal tubules. For the present study, fresh frozen tissue from 30 Wilms' tumours and corresponding non-tumour tissues were analysed. Single nucleotide polymorphisms of the E-cadherin and cadherin-11 genes were chosen and analysed for allelic inactivation by polymerase chain reaction (PCR) amplification and sequence analysis. Loss of expression of one E-cadherin allele was seen in 10% (2/20) of the informative cases. Two out of 11 informative cases (18%) showed loss of expression of one cadherin-11 allele. No length alterations of either the E-cadherin or the cadherin-11 messenger RNAs were identified using reverse transcription PCR and agarose gel electrophoresis in tumour tissue. Sequencing of the entire E-cadherin coding region in seven cases showed the wild-type sequence. These data imply that E-cadherin and cadherin-11 are not likely to play typical tumour suppressor roles in Wilms' tumour. Interestingly, the E-cadherin immunohistochemistry showed a deviation from the normal reaction pattern in 50% of the cases, with 27% (8/30) showing an apical or cytoplasmic reaction and 23% (7/30) being completely negative. Northern blot analysis revealed that the overall expression of cadherin-11 is much stronger than that of E-cadherin. In several cases, the expression levels of the two genes were inversely correlated, suggesting the existence of a regulatory mechanism. Analysis of differential expression of the various cadherins and their subsequent signal transduction pathways might contribute to a better understanding of the complexity of Wilms' tumour formation.

Activation of the Notch pathway in the hair cortex leads to aberrant differentiation of the adjacent hair-shaft layers

Little is known about the mechanisms underlying the generation of various cell types in the hair follicle. To investigate the role of the Notch pathway in this process, transgenic mice were generated in which an active form of Notch1 (Notch(DeltaE)) was overexpressed under the control of the mouse hair keratin A1 (MHKA1) promoter. MHKA-Notch(DeltaE) is expressed only in one precursor cell type of the hair follicle, the cortex. Transgenic mice could be easily identified by the phenotypes of curly whiskers and wavy, sheen pelage hair. No effects of activated Notch on proliferation were detected in hair follicles of the transgenic mice. We find that activating Notch signaling in the cortex caused abnormal differentiation of the medulla and the cuticle, two neighboring cell types that did not express activated Notch. We demonstrate that these non-autonomous effects are likely caused by cell-cell interactions between keratinocytes within the hair follicle and that Notch may function in such interactions either by directing the differentiation of follicular cells or assisting cells in interpreting a gradient emanating from the dermal papilla.

Spectrum of hSNF5/INI1 somatic mutations in human cancer and genotype-phenotype correlations

The hSNF5/INI1 gene which encodes a member of the SWI/SNF chromatin ATP-dependent remodeling complex, is a new tumor suppressor gene localized on chromosome 22q11.2 and recently shown to be mutated in malignant rhabdoid tumors. We have searched for hSNF5/INI1 mutations in 229 tumors of various origins using a screening method based on denaturing high-performance liquid chromatography. A total of 31 homozygous deletions and 36 point alterations were identified. Point mutations were scattered along the coding sequence and included 15 nonsense, 15 frameshift, three splice site, two missense and one editing mutations. Mutations were retrieved in most rhabdoid tumors, whatever their sites of occurrence, indicating the common pathogenetic origin of these tumors. Recurrent hSNF5/INI1 alterations were also observed in choroid plexus carcinomas and in a subset of central primitive neuroectodermal tumors (cPNETs) and medulloblastomas. In contrast, hSNF5/INI1 point mutations were not detected in breast cancers, Wilms' tumors, gliomas, ependymomas, sarcomas and other tumor types, even though most analyzed cases harbored loss of heterozygosity at 22q11.2 loci. These results suggest that rhabdoid tumors, choroid plexus carcinomas and a subset of medulloblastomas and cPNETs share common pathways of oncogenesis related to hSNF5/INI1 alteration and that hSNF5/INI1 mutations define a genetically homogeneous family of highly aggressive cancers mainly occurring in young children and frequently, but not always, exhibiting a rhabdoid phenotype.

A 7.5 Mb sequence-ready PAC contig and gene expression map of human chromosome 11p13-p14.1

The region p13 of the short arm of human chromosome 11 has been studied intensely during the search for genes involved in the etiology of the Wilms' tumor, aniridia, genitourinary abnormalities, mental retardation (WAGR) syndrome, and related conditions. The gene map for this region is far from being complete, however, strengthening the need for additional gene identification efforts. We describe the extension of an existing contig map with P1-derived artificial chromosomes (PACs) to cover 7.5 Mb of 11p13-14.1. The extended sequence-ready contig was established by end probe walking and fingerprinting and consists of 201 PAC clones. Utilizing bins defined by overlapping PACs, we generated a detailed gene map containing 20 genes as well as 22 anonymous ESTs which have been identified by searching the RH databases. RH maps and our established gene map show global correlation, but the limits of resolution of the current RH panels are evident at this scale. Initial expression studies on the novel genes have been performed by Northern blot analyses. To extend these expression profiles, corresponding mouse cDNA clones were identified by database search and employed for Northern blot analyses and RNA in situ hybridizations to mouse embryo sections. Genomic sequencing of clones along a minimal tiling path through the contig is currently under way and will facilitate these expression studies by in silico gene identification approaches.

Hey genes: a novel subfamily of hairy- and Enhancer of split related genes specifically expressed during mouse embryogenesis

We have identified a novel subfamily of mammalian hairy/Enhancer of split (E(spl))-related basic helix-loop-helix (bHLH) genes together with a putative Drosophila homologue. While hairy/E(spl) proteins are characterized by an invariant proline residue in the basic domain and a carboxyterminal groucho-binding WRPW motif, our genes encode a carboxyterminal KPYRPWG sequence and were thus designated as Hey genes (Hairy/E(spl)-related with YRPW motif). Furthermore, they bear a unique C-terminal TE(I/V)GAF motif and the characteristic proline is changed in all Hey family members to glycine. RNA in situ hybridization analysis revealed specific expression of Hey1 during development of the nervous system, the somites, the heart and the craniofacial region. Hey2 is similarly expressed in the somites whereas it shows a complementary expression in the heart, the craniofacial region and the nervous system. The diversity of expression patterns implies unique functions in neurogenesis, somitogenesis and organogenesis.

Fjx1, the murine homologue of the Drosophila four-jointed gene, codes for a putative secreted protein expressed in restricted domains of the developing and adult brain

The Drosophila gene four jointed (fj) codes for a secreted or cell surface protein important for growth and differentiation of legs and wings and for proper development of the eyes. Here we report the cloning of the mouse four-jointed gene (fjx1) and its pattern of expression in the brain during embryogenesis and in the adult. In the neural plate, fjx1 is expressed in the presumptive forebrain and midbrain, and in rhombomere 4, however a small rostral/medial area of the forebrain primordium is devoid of expression. Expression of fjx1 in the neural tube can be divided into three phases. (1) In the embryonic brain fjx1 is expressed in two patches of neuroepithelium: in the midbrain tectum and the telencephalic vesicles. (2) In fetal and early postnatal brain fjx1 is expressed mainly by the primordia of layered telencephalic structures: cortex (ventricular layer and cortical plate), olfactory bulb (subependymal layer and in the mitral cell layer). In addition expression is observed in the superior colliculus. (3) In the adult, fjx1 is expressed by neurones evenly distributed in the telencephalon (isocortex, striatum, hippocampus, olfactory bulb, piriform cortex), in the Purkinje cell layer of the cerebellum, and numerous medullary nuclei. In the embryo, strong expression can further be seen in the apical ectodermal ridge of fore- and hindlimbs and in the ectoderm of the branchial arches.

A sequence-ready 3-Mb PAC contig covering 16 breakpoints of the Wilms tumor/anirida region of human chromosome 11p13

A large body of evidence that links alterations of chromosome 11p13 to tumor formation and various developmental disorders has been accumulated. To address the underlying genetic events it would be helpful to have a comprehensive gene map of the region, and this is most readily achieved by generating the complete genomic sequence. Building upon previous mapping and YAC contig analysis we have established a 3-Mb sequence-ready PAC contig. It was constructed by chromosome walking and independently verified by fingerprint analysis of individual clones. The contig starts from the catalase gene on the centromeric side and reaches beyond the PAX6 gene at the 11p13/p14.1 boundary. Additional smaller contigs on either side were identified, but still have to be linked up. The 3-Mb contig spans the central region of deletions encompassing 16 chromosomal breakpoints in patients with WAGR syndrome (Wilms tumor, aniridia, genitourinary malformation, mental retardation), and its construction is an important step in facilitating functional analysis of these genes.

Analysis of WT1 target gene expression in stably transfected cell lines

The Wilms' tumour suppressor gene WT1 encodes a zinc finger protein that is mutated in a subset of Wilms' tumours. Mutation screening and animal studies revealed essential roles during development and later function of the kidneys and the entire genitourinary system. Sequence similarity suggested a possible role for WT1 as a transcription factor. Indeed, sequence specific DNA binding and transcriptional activation or repression potential could be demonstrated in transient transfection assays with various reporter constructs. To identify endogenous WT1 target genes we established HEK293 cell lines expressing the different WT1 isoforms in a tetracycline dependent manner. Differential display PCR (ddPCR) was performed on RNA from stable WT1 transfected HEK293 cell lines and two other WT1 transfected lines (G401 and Saos-2). In an extended survey of several thousand ddPCR bands only few differences in intensity were seen and none of these could unambiguously be verified as being WT1 regulated by subsequent Northern blot analysis. In addition, almost none of the WT1 target genes identified to date in transient co-transfection assays could be confirmed by either ddPCR or Northern hybridization in the three stable transfected cell lines. Among the nine genes expressed, the only exceptions were CSF1 and to a lesser extent IGF1R being induced in Saos-2/G401 and HEK293 cells, respectively. At least two of the cell lines tested had previously shown clear biological effects though -- either WT1 dependent apoptosis (Saos-2) or greatly reduced tumorigenicity (G401). This suggests that WT1 may regulate only a very small set of genes that escape the detection methods used or it may not act as a transcription factor that influences steady state levels of mRNA.

Allele loss in Wilms tumors of chromosome arms 11q, 16q, and 22q correlate with clinicopathological parameters

An extended analysis for loss of heterozygosity (LOH) on eight chromosomes was conducted in a series of 82 Wilms tumors. Observed rates of allele loss were: 9.5% (1p), 5% (4q), 6% (6p), 3% (7p), 9.8% (11q), 28% (11p15), 13.4% (16q), 8.8% (18p), and 13.8% (22q). Known regions of frequent allele loss on chromosome arms 1p, 11p15, and 16q were analyzed with a series of markers, but their size could not be narrowed down to smaller intervals, making any positional cloning effort difficult. In contrast to most previous studies, several tumors exhibited allele loss for multiple chromosomes, suggesting an important role for genome instability in a subset of tumors. Comparison with clinical data revealed a possible prognostic significance, especially for LOH on chromosome arms 11q and 22q with high frequencies of anaplastic tumors, tumor recurrence, and fatal outcome. Similarly, LOH 16q was associated with anaplastic and recurrent tumors. These markers may be helpful in the future for selecting high-risk tumors for modified therapeutic regimens.

Developmental expression patterns of mouse sFRP genes encoding members of the secreted frizzled related protein family

Development of the metanephric kidney is an experimental model system to analyze interactions between mesenchymal and epithelial cells and mesenchymal-epithelial transition. To study the underlying genetic mechanisms we employed organ culture and differential display PCR to identify genes regulated upon induction of mesenchymal cells. One of the genes found encodes the secreted frizzled related protein 2 (sFRP2) that is upregulated within 2 days of in vitro development. In vivo sFRP2 expression was likewise found in mesenchymal condensates and subsequent epithelial structures. Detailed in situ hybridization analysis revealed sFRP2 expression during development of the eye, brain, neural tube, craniofacial mesenchyme, joints, testis, pancreas and below the epithelia of oesophagus, aorta and ureter where smooth muscles develop. In a comparative analysis transcripts of the related sFRP1 and sFRP4 genes were frequently found in the same tissues as sFRP2 with their expression domains overlapping in some instances, but mutually exclusive in others. While sFRP1 is specifically expressed in the embryonic metanephros, eye, brain, teeth, salivary gland and small intestine, there is only weak expression of sFRP4 except for the developing teeth, eye and salivary gland. The interpretation of the highly specific spatial and temporal expression patterns of sFRP genes will partly depend on a better functional understanding of the interaction between wnt, fz and sFRP family members. Nevertheless, sFRP genes must play quite distinct roles in the morphogenesis of several organ systems.

Transcript map of a 900-kb genomic region in Xp22.1-p22.2: identification of 12 novel genes

The Xp22.1-p22.2 interval is a focus of interest as a number of hereditary disease loci have been mapped to this region, including X-linked nonsyndromic sensorineural deafness (DFN6), X-linked juvenile retinoschisis (RS), and several X-linked mental retardation syndromes. In the course of cloning the RS gene we have assembled YAC and PAC contigs of the 900-kb candidate region delimited by DXS418 and DXS999. In this study, we now report the construction of a first transcript map of this chromosomal interval by combining exon trapping, EST mapping, and computational gene identification methods. Overall, this strategy has led to the assembly of at least 12 novel transcripts positioned within the DXS418-DXS999 region, one of these encoding a putative protein kinase motif with significant homology to the rat p58/GTA protein kinase domain and another a putative neuronal protein with strong homology to a Drosophila transcriptional repressor.

Frasier syndrome is caused by defective alternative splicing of WT1 leading to an altered ratio of WT1 +/-KTS splice isoforms

The Wilms' tumor gene WT1 plays a key role in genitourinary development and subsequent normal function. Homozygous mutations of WT1 can be found in approximately 15% of Wilms' tumors. Furthermore, somatic heterozygous loss of WT1 is known to lead to cryptorchidism and hypospadias in males. A much more severe phenotype is seen in patients with Denys-Drash syndrome which results from heterozygous dominant-negative mutations of the gene. Characteristic features are mesangial sclerosis with early kidney failure, varying degrees of gonadal dysgenesis and high risk of Wilms' tumors. Here we show that a related disease, Frasier syndrome, characterized by focal glomerular sclerosis, delayed kidney failure and complete gonadal dysgenesis, is probably caused by specific intronic point mutations of WT1 that preferentially affect a CpG dinucleotide. Disruption of alternative splicing at the exon 9 splice donor site prevents synthesis of the usually more abundant WT1 +KTS isoform from the mutant allele. In contrast to Denys-Drash syndrome, no mutant protein is produced. The splice mutation leads to an imbalance of WT1 isoforms in vivo , as detected by RT-PCR on streak gonadal tissue. Thus, WT1 isoforms must have quite different functions, and the pathology of Frasier syndrome suggests that especially gonadal development may be particularly sensitive to imbalance or relative underrepresentation of the WT1 +KTS isoform.

Isolation and characterization of Leishmania parasites imported into Switzerland--a retrospective study

Cases of leishmaniasis imported into Switzerland were diagnosed by culture and/or Giemsa-stained smears. The cultures proved to be positive in 61 of 64 confirmed cases, whereas only 49% of Giemsa-stained smears were positive. Promastigotes were detected on average after 3.6 +/- 2.2 days. A total of 33 different isolates were characterized by isoenzyme analysis and typed as Leishmania infantum (10 cases, mainly from Europe), L. chagasi (1 case, Central America), L. major (12 cases, mainly from Africa), L. braziliensis (7 cases, South and Central America), and L. tropica (1 case, Near East). Two isolates could not be clearly classified. Correlations between species and origin or between species and type of biopsy were as expected.

Six new polymorphic microsatellite markers used for the integration of genetic and physical maps of human chromosome 7

We report the isolation and characterization of six new polymorphic dinucleotide repeat microsatellite markers (D7S1491, D7S1492, D7S1493, D7S1494, D7S1495, and D7S1496), their integration into the genetic map of human chromosome 7 by analysis of 40 CEPH (Centre d'Etude du Polymorphisme Humain) pedigrees, and their use for integration of physical and genetic maps of this chromosome.

WT1 expression alters tumorigenicity of the G401 kidney-derived cell line

Recent studies have implicated a loss of WT1 tumor suppressor gene function in the development of Wilms' tumor (WT). To determine the potential biological consequences of WT1 inactivation in these tumors, we transfected two different splice variant forms of this gene into the pediatric kidney-derived cell line G401. Introduction of this gene caused no detectable effects on the population doubling times of the cell line; proliferative capacity in soft agar was not significantly affected. However, the expression of this gene altered the morphology of the cells in culture and caused a significant suppression of tumorigenicity in the cells. Thus, the expression of WT1 in a pediatric kidney-derived cell line lacking endogenous WT1 production caused demonstrable effects on its in vitro and in vivo growth properties. These data strengthen the concept for a central role for WT1 inactivation in the etiology of this disease.

An integrated YAC clone contig for the WAGR region on human chromosome 11p13-p14.1

The WAGR syndrome (Wilms tumor, aniridia, genitourinary anomalies, and mental retardation) deletion region on chromosome 11p13 has been extensively characterized by deletion analysis and long-range restriction mapping. A dense probe set is available for this genomic region, which harbors a number of disease gene loci, some of which still are not cloned. The identification of candidates for these genes would be greatly facilitated by a complete gene map for this chromosomal segment. As an initial step toward this goal, we have isolated the entire region in 58 overlapping YAC clones. The contig spanning 8 Mb from RAG1 to KCNA4 has been assembled by STS and probe content mapping for 76 loci with an average spacing of about 100 kb. A subset of clones has been analyzed by PFG analysis to position these within the known physical map. Common microsatellite markers permit an alignment of the YAC contig with the genetic and radiation hybrid maps of chromosome 11. Ten known genes, some with much more refined map positions, are placed in the contig. The severalfold coverage of 11p13-p14.1 provides a reliable resource for the future development of a complete gene map of this region.

cDNA sequence, genomic organization, and evolutionary conservation of a novel gene from the WAGR region

A new gene (239FB) with predominant and differential expression in fetal brain has recently been isolated from a chromosome 11p13-p14 boundary area near FSHB. The corresponding mRNA has an open reading frame of 294 amino acids, a 3' untranslated region of 1247 nucleotides, and a highly GC-rich 5' untranslated region. The coding and 3' UT sequence is specified by 6 exons within nearly 87 kb of isolated genomic locus. The 5' end region of the transcript maps adjacent to the only genomically defined CpG island in a chromosomal subregion that may be associated with part of the mental retardation of some WAGR (Wilms tumor, aniridia, genitourinary anomalies, and mental retardation) syndrome patients. In addition to nucleotide and amino acid similarity to an EST from a normalized infant brain cDNA library, the predicted protein has extensive similarity to two Caenorhabditis elegans polypeptides of, as yet, unknown function. The 239FB locus is, therefore, likely part of a family of genes with two members expressed in human brain. The extensive conservation of the predicted protein suggests a fundamental function of the gene product and will enable evaluation of the role of the 239FB gene in neurogenesis in model organisms.

Identification of optimized target sequences for the GLI3 zinc finger protein

GLI3 represents an important control gene for development and differentiation of several body structures. Reduction in gene dosage already leads to severe perturbation, especially of limb morphogenesis. The gene encodes a zinc finger protein that likely functions as a transcriptional modulator. Because the five zinc fingers should be capable of recognizing an extended stretch of genomic DNA, we sought to identify sequences bound by GLI3 that may facilitate the search for target genes acting downstream of GLI3. Starting from the nonamer DNA binding sequence of the highly related GLI protein, we employed an oligonucleotide selection protocol to determine an optimized binding sequence for the GLI3 protein. The resulting sequence bound by the GLI3 zinc fingers consists of 16 nucleotides and shows a high degree of similarity to sequences bound by the GLI and tra-1 proteins. Comparison with protein-DNA interactions in the known crystal structure of the GLI-DNA complex suggests relevant interactions of additional amino acids of GLI3 with its target site. The newly identified GLI3 target sequence should prove very useful for both the structural analysis of the protein-DNA complex and the search for genes whose expression is subject to regulation by the GLI3 gene product.

CpG island clones for chromosome 11p--a resource for mapping and gene identification

A NotI end fragment library has been constructed for human Chromosome (Chr) 11p. Seventy-two clones were mapped to chromosomal subregions by use of somatic cell hybrids. The clones detect 44 different CpG islands, and we have isolated cosmid contigs for 36 of them. Extrapolation from the known 11p13 NotI restriction map suggests that every second CpG island from 11p containing a Not site is already represented in the clone collection. By sequence analysis all of the 11p13 clones exhibit typical features of CpG islands, and cross-species hybridization has been detected with at least one fragment in most cases. The cosmids serve as valuable linking clones for long-range restriction mapping. They also provide excellent starting material for transcript isolation procedures to identify genes on chromosome 11p associated with developmental anomalies and various tumor types. Several transcribed sequences have already been isolated with some of these clones.

Isolation and characterization of a cosmid contig for the GCPS gene region

The zinc finger gene GLI3 has been shown to be involved in the embryonal development of the limbs and skull. Mutations in GLI3 lead to the development of the human Greig cephalopolysyndactyly syndrome (GCPS) and the mouse mutations extra toes (Xt) and anterior digit deformity (add). The GCPS locus on human chromosome 7p13 has recently been isolated in a yeast artificial chromosome (YAC) contig. Here, we describe the establishment of a cosmid contig that was derived from two of the YAC clones, that spans 550 kb of human DNA, and that includes the GLI3 gene. In this contig, three GCPS translocation breakpoints have been mapped to distinct EcoRI fragments in the 3' half of the gene. In addition, exon-carrying fragments have been identified and the size of the GLI3 gene could be determined as at least 280 kb. The gene is flanked by a CpG island that lies on the 5' side and that is in close proximity to the first exon detected by the cloned GLI3 cDNA. Further upstream, five segments were found that have been conserved between man and mouse. In the mouse, this region has been characterized as the transgene integration site resulting in the add phenotype. Both the CpG island and the conserved regions are probable candidates for a search for GLI3 promoter and control elements.

A WAGR region gene between PAX-6 and FSHB expressed in fetal brain

Developmental delay or mental retardation is a frequent component of multi-system anomaly syndromes associated with chromosomal deletions. Isolation of genes involved in the mental dysfunction in these disorders should define loci important in brain formation or function. We have identified a highly conserved locus in the distal part of 11p13 that is prominently expressed in fetal brain. Minimal expression is observed in a number of other fetal tissues. The gene maps distal to PAX-6 but proximal to the loci for brain-derived neurotrophic factor (BDNF) and the beta subunit of follicle stimulating hormone (FSHB), within a region previously implicated in the mental retardation component of some WAGR syndrome patients. Within fetal brain, the corresponding transcript is prominent in frontal, motor and primary visual cortex as well as in the caudate-putamen. The characteristics of this gene, including the striking evolutionary conservation at the locus, suggest that the encoded protein may function in brain development.

An ordered NotI fragment map of human chromosome band 11p15

An ordered NotI fragment map containing over 60 loci and encompassing approximately 17 Mb has been constructed for human chromosome band 11p15. Forty-two probes, including 11 NotI-linking cosmids, were subregionally mapped to 11p15 using a subset of the J1-deletion hybrids. These and 23 other probes defining loci previously mapped to 11p15 were hybridized to genomic DNA digested with NotI and 5 other infrequently cleaving restriction enzymes and separated by pulsed-field gel electrophoresis. Thirty-nine distinct NotI fragments were detected encompassing approximately 85% of the estimated length of 11p15. The predicted order of the gene loci used is cen-MYOD1-PTH-CALCA-ST5-RBTN1-HPX-HBB-RRM1 -TH/INS/IGF2-H19-CTSD-MUC2-DRD4-HRAS - RNH-tel. This map will allow higher resolution mapping of new 11p15 markers, facilitate positional cloning of disease genes, and provide a framework for the physical mapping of 11p15 in clone contigs.

Isolation of a yeast artificial chromosome contig spanning the Greig cephalopolysyndactyly syndrome (GCPS) gene region

Disruption of the zinc finger gene GLI3 has been shown to be the cause of Greig cephalopolysyndactyly syndrome (GCPS), at least in some GCPS translocation patients. To characterize this genomic region on human chromosome 7p13, we have isolated a YAC contig of more than 1000 kb including the GLI3 gene. In this contig the gene itself spans at least 200-250 kb. A CpG island is located in the vicinity of the 5' region of the known GLI3 cDNA, implying a potential promoter region.

Confirmation of the localization of the human recombination activating gene 1 (RAG1) to chromosome 11p13

The human recombination activating gene 1 (RAG1) has previously been mapped to chromosomes 14q and 11p. Here we confirm the chromosome 11 assignment by two independent approaches: autoradiographic and fluorescence in situ hybridization to metaphase spreads and analysis of human-hamster somatic cell hybrid DNA by the polymerase chain reaction (PCR) and Southern blotting. Our results unequivocally localize RAG1 to 11p13.

Infrequent mutation of the WT1 gene in 77 Wilms' Tumors

Homozygous deletions in Wilms' tumor DNA have been a key step in the identification and isolation of the WT1 gene. Several additional loci are also postulated to contribute to Wilms' tumor formation. To assess the frequency of WT1 alterations we have analyzed the WT1 locus in a panel of 77 Wilms' tumors. Eight tumors showed evidence for large deletions of several hundred or thousand kilobasepairs of DNA, some of which were also cytogenetically detected. Additional intragenic mutations were detected using more sensitive SSCP analyses to scan all 10 WT1 exons. Most of these result in premature stop codons or missense mutations that inactivate the remaining WT1 allele. The overall frequency of WT1 alterations detected with these methods is less than 15%. While some mutations may not be detectable with the methods employed, our results suggest that direct alterations of the WT1 gene are present in only a small fraction of Wilms' tumors. Thus, mutations at other Wilms' tumor loci or disturbance of interactions between these genes likely play an important role in Wilms' tumor development.

Sequence of the WT1 upstream region including the Wit-1 gene

The Wilms tumor gene WT1 encodes a Cys2His2-type zinc finger protein that can bind DNA and function as a transcriptional regulator. The pathological spectrum of tumorigenesis and various developmental defects produced by different WT1 alterations suggests that WT1 controls a number of subsequent effector genes. To define the role of WT1 in these developmental processes it will be important to elucidate mechanisms that govern expression of WT1 itself. To facilitate mapping of the WT1 promoter region and 5' control elements we have determined the sequence upstream of the WT1 transcription unit. This includes the Wit-1 gene that is transcribed in the opposite direction.

Homozygous inactivation of WT1 in a Wilms' tumor associated with the WAGR syndrome

Wilms' tumor is a childhood nephroblastoma that is postulated to arise through the inactivation of a tumor suppressor gene by a two-hit mechanism. A candidate 11p13 Wilms' tumor gene, WT1, has been cloned and shown to encode a zinc finger protein. Patients with the WAGR syndrome (Wilm's tumor, aniridia, genitourinary abnormalities, and mental retardation) have a high risk of developing Wilms' tumor and they carry constitutional deletions of one chromosome 11 allele encompassing the WT1 gene. Analysis of the remaining WT1 allele in a Wilms' tumor from a WAGR patient revealed the deletion of a single nucleotide in exon 7. This mutation likely played a key role in tumor formation, as it prevents translation of the DNA-binding zinc finger domain that is essential for the function of the WT1 polypeptide as a transcriptional regulator.

Pericentric intrachromosomal insertion responsible for recurrence of del(11)(p13p14) in a family

The combined use of qualitative and quantitative analysis of 11p13 polymorphic markers together with chromosomal in situ suppression hybridization (CISS) with biotin labeled probes mapping to 11p allowed us to characterize a complex rearrangement segregating in a family. We detected a pericentric intrachromosomal insertion responsible for recurrence of del(11)(p13p14) in the family: an insertion of brand 11p13-p14 carrying the genes for predisposition to Wilms' tumor, WT1, and for aniridia, AN2, into the long arm of chromosome 11 in 11q13-q14. Asymptomatic balanced carriers were observed over three generations. Classical cytogenetics had failed to detect this anomaly in the balanced carriers, who were first considered to be somatic mosaics for del(11)(p13). Two of these women gave birth to children carrying a deleted chromosome 11, most likely resulting from the loss of the 11p13 band inserted in 11q. Although in both cases the deletion encompassed exactly the same maternally inherited markers, there was a wide variation in clinical expression. One child, with the karyotype 46,XY, del(11)(p13p14), presented the full-blown WAGR syndrome with aniridia, mental retardation, Wilms' tumor, and pseudohermaphroditism, but also had proteinuria and glomerular sclerosis reminiscent of Drash syndrome. In contrast, the other one, a girl with the karyotype 46,XX,del(11)(p13), only had aniridia. Although a specific set of mutational sites has been observed in Drash patients, these findings suggest that the loss of one copy of the WT1 gene can result in similar genital and kidney abnormalities.

Distinct molecular origins for Denys-Drash and Frasier syndromes

The direct involvement of the Wilm's tumor suppressor gene (WT1) in Denys-Drash syndrome through mutations within exons 8 or 9 has recently been established. The absence of such alterations in three patients with Frasier syndrome provides a molecular basis for distinguishing these two syndromes that are associated with streak gonads, pseudohermaphroditism and renal failure.

Aspects of sandfly biology in southern Switzerland

During three field surveys of phlebotomine sandflies in the region of Sessa, Minor Malcantone, southern Switzerland, annually 1987-89, Phlebotomus perniciosus and P. mascittii were caught regularly by means of light traps, but only when the traps were in close association with humans. The most productive catching sites were in the middle of Sessa village, in basements or partially closed shelters in the immediate vicinity of human dwellings. All catching sites outside the village were negative. The only other sandfly species caught was Sergentomyia minuta, four specimens only. P.perniciosus and P.mascittii always occurred together and were found to feed--at least occasionally--on human blood. Glucose and fructose were identified in wild-caught sandflies of both species. A breeding place of P. mascittii was identified in the basement of a house in the middle of Sessa. Analyses of soil samples revealed moderately loamy humus with a slightly acidic pH (5.6).