Reevaluation of the Incidence of Thromboembolic Complications in Congenital Factor XII Deficiency

To further elucidate the debated role of hereditary FXII deficiency as a thrombophilic risk factor this follow-up study on 65 subjects out of 12 Swiss families was undertaken (follow-up: 6 yrs). Fifteen severely FXII deficient subjects (FXII:C < 1%), 35 partially FXII deficient subjects (FXII:C ≥ 1-59%), 10 with normal FXII values (FXII:C ≥ 70%), and 5 non-classifiable subjects (FXII:C ≥ 60-69%) were reevaluated. Eight subjects (4 severely and 3 partially FXII deficient, 1 non-classifiable) were newly enrolled. Four instances of deep vein thrombosis, one superficial vein thrombosis and one myocardial infarction were noted in 2 out of 19 severely FXII deficient subjects during a total life-time period of 866.6 patient-years. In 38 partially FXII deficient subjects (1862.8 patient-years) one ischemic cerebrovascular stroke and one superficial vein thrombosis were recorded in 2 individuals. The 10 subjects with normal FXII values (498.2 patient-years) remained thrombosis-free. One superficial vein thrombosis occurred in an unclassifiable woman. None of the 3 different FXII gene defects revealed in our patients was specifically associated with thromboembolic complications. Kaplan-Meier analysis of thrombosis-free survival suggests that hereditary partial (and probably severe) FXII deficiency does not constitute a thrombophilic condition.

Der Einfluß organischer Kieselsäure-Verbindungen auf das Wachstum von Aspergillus niger und Triticum

Der Einfluß von Kohlenhydratkieselsäure-Verbindungen auf das Wachstum verschiedener Organismen wird an den Beispielen Aspergillus niger und Triticum (Weizensamen) gezeigt.

Die Reaktion ist Ο2-abhängig. Eine Aufnahme der organisch gebundenen Quarzkieselsäure von den verschiedenen Organismen konnte quantitativ verfolgt werden. Sie beeinflußte den N-Gehalt und die Kohlenhydratbildung bei Aspergillus niger.

Pluripotent embryonic stem cells and multipotent adult germline stem cells reveal similar transcriptomes including pluripotency-related genes

DNA microarray analysis was performed with mouse multipotent adult germline stem cells (maGSCs) and embryonic stem cells (ESCs) from different genetic backgrounds cultured under standard ESC-culture conditions and under differentiation-promoting conditions by the withdrawal of the leukemia inhibitory factor (LIF) and treatment with retinoic acid (RA). The analyzed undifferentiated cell lines are very similar based on their global gene expression pattern and show 97-99% identity dependent on the analyzed background. Only 621 genes are differentially expressed in cells derived from mouse 129SV-background and 72 genes show differences in expression in cells generated from transgenic Stra8-EGFP/Rosa26-LacZ-background. Both maGSCs and ESCs express the same genes involved in the regulation of pluripotency and even show no differences in the expression level of these genes. When comparing maGSCs with previously published signature genes of other pluripotent cell lines, we found that maGSCs shared a very similar gene expression pattern with embryonic germ cells (EGCs). Also after differentiation of maGSCs and ESCs the transcriptomes of the cell lines are nearly identical which suggests that both cell types differentiate spontaneously in a very similar way. This is the first study, at transcriptome level, to compare ESCs and a pluripotent cell line derived from an adult organism (maGSCs).

The nucleotide sequence of boar transition protein 2 (TNP2) cDNA and haploid expression of the gene during spermatogenesis

A cDNA clone coding for boar transition protein 2 (TNP 2) was isolated from a randomly primed cDNA library of boar testis. Sequence analysis revealed an open reading frame of 414 bp (corresponding to 138 amino acids), 33 bp of the 5' untranslated and about 300 bp of the 3' untranslated region. As compared to TNP 2 of mouse and rat, similarity with TNP 2 of the boar is approximately 70% at the nucleotide level and only about 40% on the basis of amino acid sequence. The similarity between boar and bull TNP2 is 77% and 64%, respectively. Northern blot experiments with RNA of different boar tissues and in situ hybridization on mature boar testis sections revealed testis-specific expression of the TNP 2 gene which is restricted to haploid germ cells. Hybridization experiments of boar TNP2 cDNA with testicular RNA of boar, bull, rat and mouse revealed decreasing intensities of the hybridization signals. With human testicular RNA no hybridization could be obtained.

Impairment of gastric acid secretion and increase of embryonic lethality in Foxq1-deficient mice

The mouse Foxq1 gene, also known as Hfh1, encodes a winged helix/forkhead transcription factor. In adult mice, Foxq1 is highly expressed in kidney and stomach. Here, we report that Foxq1 is expressed during prenatal and postnatal stomach development and the transcripts are restricted to acid secreting parietal cells. Mice homozygous for a deletion of the Foxq1 locus on a 129/Sv x C57BL/6J hybrid genetic background display variable phenotypes consistent with requirement of the gene during embryogenesis. Approximately 50% of Foxq1-/- embryos die in utero. Surviving homozygous mutants are normal and fertile, and have a silky shiny coat. Although the parietal cell development is not affected in the absence of Foxq1, there is a lack of gastric acid secretion in response to various secretagogue stimuli. Ultrastructural analysis suggests that the gastric acid secretion defect in Foxq1-deficient mice might be due to impairment in the fusion of cytoplasmic tubulovesicles to the apical membrane of secretory canaliculi.

The putative peroxisomal gene Pxt1 is exclusively expressed in the testis

Genes reported to be crucial for spermatogenesis are often exclusively expressed in the testis. We have identified a novel male germ cell-specific expressed gene named peroxisomal testis specific 1 (Pxt1) with expression starting at the spermatocyte stage during mouse spermatogenesis. The putative amino acid sequence encoded by the cDNA of the Pxt1 gene contains a conserved Asn-His-Leu (NHL)-motif at its C-terminal end, which is characteristic for peroxisomal proteins. Pxt1-EGFP fusion protein is co-localized with known peroxisomal marker proteins in transfected NIH3T3 cells. In addition, we could demonstrate that the peroxisomal targeting signal NHL is functional and responsible for the correct subcellular localization of the Pxt1-EGFP fusion protein. In male germ cells peroxisomes were reported only in spermatogonia. The Pxt1 gene is so far the first gene coding for a putative peroxisomal protein which is expressed in later steps of spermatogenesis, namely in pachytene spermatocytes.

Asthenoteratozoospermia in mice lacking testis expressed gene 18 (Tex18)

Testis expressed gene 18 (Tex18) is a small gene with one exon of 240 bp, which is specifically expressed in male germ cells. The gene encodes for a protein of 80 amino acids with unknown domain. To investigate the function of (Tex18) gene, we generated mice with targeted disruption of the (Tex18) gene by homologous recombination. Homozygous mutant males on a mixed genetic background (C57BL/6J x 129/Sv) are fertile, while they are subfertile on the 129/Sv background, although mating is normal. We showed that Tex18(-/-) males are subfertile because of abnormal sperm morphology and reduced motility, which is called asthenoteratozoospermia, suggesting that (Tex18) affects sperm characteristics. Maturation of spermatids is unsynchronized and partially impaired in seminiferous tubules of Tex18(-/-) mice. Electron microscopical examination demonstrated abnormal structures of sperm head. In vivo experiments with sperm of Tex18(-/-) 129/Sv mice revealed that the migration of spermatozoa from the uterus into the oviduct is reduced. This result is supported by the observation that sperm motility, as determined by the computer-assisted semen analysis system, is significantly affected, compared to wild-type spermatozoa. Generation of transgenic mice containing Tex18-EGFP fusion construct revealed a high transcriptional activity of (Tex18) during spermiogenesis, a process with morphological changes of haploid germ cells and development to mature spermatozoa. These results indicate that (Tex18) is expressed predominantly during spermatid differentiation and subfertility of the male Tex18(-/-) mice on the 129/Sv background is due to the differentiation arrest, abnormal sperm morphology and reduced sperm motility.

Failure of phospholipid hydroperoxide glutathione peroxidase expression in oligoasthenozoospermia and mutations in the PHGPx gene

Phospholipid hydroperoxide glutathione peroxidase (PHGPx) is a selenoprotein belonging to the family of glutathione peroxidases. PHGPx has long been considered a major antioxidant that, in cooperation with vitamin E, protects biomembranes. To determine the expression pattern of PHGPx mRNA in human, quantitative RT-polymerase chain reaction (PCR) analyses using RNA from different embryonal and adult tissues were performed. A predominant expression was found in testes. In spermatozoa, PHGPx was found to be localized in the mid-piece of spermatozoa. We studied the relationship between spermatozoa PHGPx expression, mutations in PHGPx gene and human oligoasthenozoospermia, a defect in which both the number and the motility of spermatozoa are significantly below normal. Spermatozoa specimens from 45 infertile males were analysed for fertility-related parameters according to World Health Organisation and were classified as suffering from oligoasthenozoospermia. Two patients (4.44%) showed no expression of PHGPx and in nine patients (20.00%), a reduced expression of the enzyme was observed. DNA sequences of various regions of the PHGPx gene (coding, 5'flanking region and intron 1) from these patients and 58 fertile volunteers were analysed for mutations by PCR amplification and direct sequencing. Sequence data revealed no cause/effect relationship for any of the variants. From these data it can be concluded that oligoasthenozoospermia is associated with a decrease in the level of expression of PHGPx in the spermatozoa of some infertile men (24.44%), but is not linked to mutations in PHGPx gene.

Mutation analysis in hereditary haemorrhagic telangiectasia in Germany reveals 11 novel ENG and 12 novel ACVRL1/ALK1 mutations

Hereditary haemorrhagic telangiectasia (HHT) is an autosomal-dominant disease characterized by recurrent epistaxis, mucocutaneous telangiectasias and visceral arteriovenous malformations. Mutations in endoglin (ENG) and activin A receptor type II-like kinase 1 (ACVRL1 or ALK1) have been found in patients with HHT. We have screened a total of 51 unselected German index cases with the suspected diagnosis of HHT. We identified 30 different mutations in 32 cases (62.7%) by direct sequencing. Among these mutations, 11 of 13 ENG mutations and 12 of 17 ACVRL1 mutations were not previously reported in the literature. Two of the ACVRL1 mutations were each shared by two families. An analysis of the genotype-phenotype correlation is consistent with a more common frequency of pulmonary arteriovenous malformations in patients with ENG mutations than in patients with ACVRL1 mutations in our collective.

The scoliosis (sco) mouse: a new allele of Pax1

We describe the spontaneous mutant mouse scoliosis (sco) that carries a new allele of Pax1 (un-i, undulated intermediate). The Pax1(un-i) allele is lacking the 5'-flanking region and exon 1 to 4 which is mapped to nt -2636 to -640 and -272 to 4271 of the Pax1 gene. Homozygous mice show a mild form of the known phenotypes of other Pax1 mutants. Adult mice have a lumbar scoliosis and kinky tails. In homozygous embryos the skeleton ossifies early, ossification centers of the vertebral bodies are fused with the ossification centers of the pedicles. Neural arches and spinous processes are underdeveloped but the pedicles and transverse processes are overdeveloped which is in contrast to other Pax1 mutants. In the scapula, the acromion is missing and the deltoid tuberosity of the proximal humerus is shortened and thickened. Among the inner organs the thymus development is affected. In late embryos, the thymus is small and thymocyte numbers are reduced. T-cell development from CD4- and CD8- double negative (DN) to CD4+ and CD8+ double positive (DP) is decelerated. The percentage of CD90+ cells is also reduced but in contrast to other Pax1 mutants no alteration of the expression level of the CD90 (Thy-1) could be found.

Synergistic effects of germ cell expressed genes on male fertility in mice

Over 200 genes have been shown to be associated with infertility in mouse models. However, knockout mice reveal unexpected functional redundancy of some germ cell expressed genes. Single null mutations in mouse genes encoding four male germ cell proteins, transition protein 2 (Tnp2), proacrosin (Acr), histone H1.1 (H1.1), histone H1t (H1t) and sperm mitochondria-associated cysteine-rich protein (Smcp) have been generated and analysed. Tnp2 is believed to participate in the removal of the nuclear histones and initial condensation of the spermatid nucleus. Proacrosin is an acrosomal protease synthesized as a proenzyme and activated into acrosin during the acrosome reaction. The linker histone subtype H1.1 belongs to the group of main-type histones and is synthesized in somatic tissues as well as in germ cells during the S-phase of the cell cycle. The histone gene Hist1h1t is expressed exclusively in spermatocytes and may have a function in establishing an open chromatin structure for the replacement of histones by transition proteins and protamines. Sperm mitochondria-associated cysteine-rich protein (Smcp) is a major structural element of the mitochondria in the midpiece of the sperm tail. Male mutant mice lacking any of these proteins show no apparent defects in spermatogenesis or fertility. To examine the synergistic effects of these proteins in spermatogenesis and during fertilization four lines of double knockout mice Hist1h1a/Mcsp, Hist1h1t/Mcsp, Tnp2/Mcsp and Acr/Mcsp were established. It was found that even when knockout mice are heterozygous for one allele (-/+) and homozygous for the other allele (-/-), mice were subfertile. Homozygous double knockout mice of all four lines are nearly infertile. However, in the four homozygous double knockout mouse lines, different characteristic abnormalities are prominently manifested: In Hist1h1a-/-/Mcsp-/- the migration of spermatozoa is disturbed in female genital tract, in Hist1h1t-/-/Mcsp-/- spermatozoa show morphological head abnormalities, in Tnp2-/-/Mcsp-/- the motility of sperm is affected, and in Acr-/-/Mcsp-/- the sperm-oocyte interaction is impaired. These findings indicate strongly that male germ cell expressed genes have synergistic effects on male fertility.

Novel mutations in the Atlastin gene (SPG3A) in families with autosomal dominant hereditary spastic paraplegia and evidence for late onset forms of HSP linked to the SPG3A locus

Hereditary spastic paraplegias (HSP) comprise a genetically and clinically heterogeneous group of neurodegenerative disorders characterised by progressive spasticity and hyperreflexia of the lower limbs. Autosomal dominant hereditary spastic paraplegia linked to the SPG3A locus on chromosome 14q11-21 accounts for approximately 10% of autosomal dominant hereditary spastic paraplegia (ADHSP). It is caused by mutations in the SPG3A gene encoding the protein atlastin. To date, only five disease-causing mutations in the SPG3A gene have been described. We analysed 13 SPG4-negative families for mutations in the SPG3A gene and identified a mutation in 38% (5/13). Two of the mutations are novel, c.481G>C (p.A161P) and c.740A>C (p.H247P). One of the novel mutations was found both in a family with early onset of symptoms and in a late onset family. Furthermore, we report on numerous polymorphisms detected in the SPG3A gene.

[Genetic causes of male infertility]

7% of all human males suffer from infertility. In at least 10% of these males infertility is due to genetic causes. Because modern reproduction techniques like ICSI (intracytoplasmic sperm injection) can help the couples to overcome infertility, it is mandatory to analyze underlying genetic causes of male infertility. If infertility in a male is due to a genetic defect, the risk of the respective couple for abortuses or malformed children is increased. The main and relevant causes for male infertility known to day are: numerical and structural chromosomal aberrations, meiotic defects, microdeletions in the region q11.21-23 of the Y-chromosome, mutations in the gene for cystic fibrosis and genetically determined syndromes in which infertility is a symptom. The present knowledge concerning these genetic causes of male infertility is pointed out.

Coeliac disease: in vivo toxicity of the putative immunodominant epitope

BACKGROUND

Peptides from alpha-gliadins have been used to characterise the immunodominant coeliac toxic epitope. A peptide corresponding to amino acid residues 57-73 of A-gliadin causes peripheral blood mononuclear cells from coeliac patients to secrete interferon gamma (IFN-gamma); gluten specific small intestinal T cell clones proliferate in response to peptides corresponding to residues 57-68 and 62-75 of alpha-gliadins. We wished to investigate whether a peptide corresponding to residues 56-75 of alpha-gliadins exacerbates coeliac disease in vivo.

METHODS

Four adults with coeliac disease, all of whom were on a gluten free diet, underwent three challenges. Peptic-tryptic gliadin (PTG 1 g) served as a positive control. The test peptide and a negative control peptide were studied on separate occasions. The peptides were instilled into the duodenum and biopsies were taken before the infusion, and two, four, and six hours after commencing the infusions, using a Quinton hydraulic multiple biopsy capsule. Biopsy specimens were assessed blindly for villus height to crypt depth ratio (VH:CD), enterocyte cell height (ECH), and intraepithelial lymphocyte (IEL) count. We used the Mann-Whitney U test, with 95% confidence intervals, for statistical analysis.

RESULTS

VH:CD and ECH fell, and IEL increased significantly 4-6 hours after commencing infusions with both PTG and the test peptide in all subjects. The negative control peptide caused no significant changes to villus morphology, enterocyte height, or IEL count in any patient.

CONCLUSION

We have confirmed that the putative immunodominant epitope, a peptide corresponding to residues 56-75 of alpha-gliadins, exacerbates coeliac disease in vivo.

Coeliac disease: in vivo toxicity of the putative immunodominant epitope

BACKGROUND

Peptides from alpha-gliadins have been used to characterise the immunodominant coeliac toxic epitope. A peptide corresponding to amino acid residues 57-73 of A-gliadin causes peripheral blood mononuclear cells from coeliac patients to secrete interferon gamma (IFN-gamma); gluten specific small intestinal T cell clones proliferate in response to peptides corresponding to residues 57-68 and 62-75 of alpha-gliadins. We wished to investigate whether a peptide corresponding to residues 56-75 of alpha-gliadins exacerbates coeliac disease in vivo.

METHODS

Four adults with coeliac disease, all of whom were on a gluten free diet, underwent three challenges. Peptic-tryptic gliadin (PTG 1 g) served as a positive control. The test peptide and a negative control peptide were studied on separate occasions. The peptides were instilled into the duodenum and biopsies were taken before the infusion, and two, four, and six hours after commencing the infusions, using a Quinton hydraulic multiple biopsy capsule. Biopsy specimens were assessed blindly for villus height to crypt depth ratio (VH:CD), enterocyte cell height (ECH), and intraepithelial lymphocyte (IEL) count. We used the Mann-Whitney U test, with 95% confidence intervals, for statistical analysis.

RESULTS

VH:CD and ECH fell, and IEL increased significantly 4-6 hours after commencing infusions with both PTG and the test peptide in all subjects. The negative control peptide caused no significant changes to villus morphology, enterocyte height, or IEL count in any patient.

CONCLUSION

We have confirmed that the putative immunodominant epitope, a peptide corresponding to residues 56-75 of alpha-gliadins, exacerbates coeliac disease in vivo.

The giant B chromosome of the cyprinid fish Alburnus alburnus harbours a retrotransposon-derived repetitive DNA sequence

The cyprinid fish Alburnus alburnus possesses one of the largest supernumerary chromosomes in all vertebrates. In the present study, amplified fragment length polymorphism analyses (AFLP) and fluorescence in-situ hybridization (FISH) were performed in order to characterize these extraordinary chromosomes in detail. Sequence analysis of the B chromosome-specific DNA revealed a strong homology to a Drosophila Gypsy/Ty3 retrotransposon and also to a medaka (Oryzias latipes) one. The sequence is highly abundant on the B chromosome but undetectable in the normal A chromosome complement. It is also absent from the B chromosome of the closely related species, Rutilus rutilus, suggesting a specific spreading of the mobile element during evolution of the giant supernumerary chromosome within A. alburnus. Meitotic chromosomes were in-situ hybridized with the B chromosome-specific probe, documenting that the additional chromosome behaves as an autopaired ring chromosome in diakineses. Our results suggest that the supernumerary chromosome of A. alburnus is not derived from the normal chromosome complement but has evolved independently.

Identification and characterization of NIF3L1 BP1, a novel cytoplasmic interaction partner of the NIF3L1 protein

The NIF3L1 protein is strongly conserved during evolution from bacteria to mammals and recently its function in neuronal differentiation has been demonstrated. In the present study we identified novel binding partners of human NIF3L1 by screening a HeLa cDNA-library using the yeast two-hybrid system. We could show that the NIF3L1 protein is interacting with itself and with the NIF3L1 binding protein 1 (NIF3L1 BP1), a novel protein of 23.67kDa bearing a putative leucine zipper domain. Furthermore, both interactions were confirmed using the mammalian two-hybrid system. Deletion analyses clearly demonstrated that a C-terminal region of 100 amino acids of the NIF3L1 BP1 is sufficient for the interaction with NIF3L1. The NIF3L1 BP1 is ubiquitously expressed and cotransfection experiments revealed that NIF3L1 and NIF3L1 BP1 interact in the cytoplasm of human LNCaP cells. This study provides novel insights into the cellular function of the NIF3L1 protein.

Generation and characterization of a transgenic mouse with a functional human TSPY

To generate an animal model that is suitable for the analysis of regulation and expression of human testis-specific protein, Y-encoded TSPY, a transgenic mouse line, TgTSPY9, harboring a complete structural human TSPY gene was generated. Fluorescence in situ hybridization and Southern analyses show that approximately 50 copies of the human TSPY transgene are integrated at a single chromosomal site that maps to the distal long arm of the Y chromosome. The transgene is correctly transcribed and spliced according to the human pattern and is mainly expressed in testicular tissue, with spermatogonia and early primary spermatocytes (leptotene and zygotene) as expressing germ cells. TSPY transgenic mice are phenotypically normal, and spermatogenesis is neither impaired nor enhanced by the human transgene. The present study shows that a human TSPY gene integrated into the mouse genome follows the human expression pattern although murine tspy had lost its function in rodent evolution millions of years ago.

Characterization, expression pattern and chromosomal localization of the spermatogenesis associated 6 gene (Spata6)

We report the cloning and characterization of the spermatogenesis associated 6 gene (Spata6) encoding a predicted protein of 488 amino acids. It exhibits similarity with the motor domain of kinesin related proteins and with the Caenorhabditis elegans neural calcium sensor protein (NCS-2). The gene encodes three mRNAs of approximately 2.6, approximately 1.8 and approximately 1.2 kb. The expression of the 2.6 kb mRNA is detected at low levels in testis, ovary, thymus and placenta, while the 1.8 and 1.2 kb transcripts are exclusively expressed in testis. The 1.8 and 1.2 kb transcripts are specifically expressed in haploid germ cells. Data from in situ hybridization experiments suggested that mRNA expression of Spata6 in spermatids is higher than in spermatocytes and spermatogonia. RT-PCR analysis and whole mount in situ hybridization demonstrate that the Spata6 transcript is expressed during embryonic development and is localized in neural tube, somites and limb buds of mouse embryo. The Spata6 gene consists of 15 exons ranging in size between 40 and 596 bp. The 2.6 and 1.8 kb transcripts have different 5' untranslated sequences but have the same translational initiation site and therefore may encode the same protein with a predicted molecular weight of 49.7 kDa. The 1.2 kb transcript is derived from a proximal promoter between exons 7 and 8, and contains a translation initiation codon AUG, which is in frame with initiator AUG codon of the 2.6 and 1.8 kb transcripts. Therefore, the 1.2 kb transcript may code for a truncated protein of 32 kDa. Western blot analysis with the antiserum raised against a synthetic peptide from the C-terminal of the deduced Spata6 protein detects only a single protein of 53 kDa in all tissues studied. The Spata6 gene was localized to chromosome 5, region q34-35 in the rat and to chromosome 1, region p32-35 in the human. In an effort to determine the function of Spata6, we inactivated the mouse gene in embryonic stem cells through homologous recombination. Although the heterozygous mutant cells were able to generate low coat colour chimeric mice, all chimeras did not transmit the targeted allele to their progeny suggesting that a high contribution of Spata6(+/-) cells lead to the lethality of the chimeric embryos.

Investigation of the putative immunodominant T cell epitopes in coeliac disease

BACKGROUND

Coeliac disease (CD) is an enteropathy mediated by gluten specific T cells which secrete interferon gamma (IFN-gamma) when stimulated by gluten peptides presented by HLA-DQ2 or DQ8 molecules. Residues 62-75 of alpha(2) gliadin have been proposed as the immunodominant epitope in the majority of CD patients. Deamidation by tissue transglutaminase (tTG) of the glutamine (Q) at position 65 to glutamic acid (E) is essential for T cell stimulation.

AIMS

To investigate the antigenicity of this peptide and to establish whether its T cell activating properties can be downregulated by the formation of altered peptide ligands.

PATIENTS

Individuals with known CD.

METHODS

Peptide G4 corresponding to alpha(2) gliadin residues 62-75, Q-E65 and analogues, substituting each amino acid, except E65, in turn for alanine residues, were synthesised. Small intestinal biopsies were obtained from patients. Biopsies were cultured overnight with a peptic/tryptic digest of gliadin (PTG). Lymphocytes were cultured and restimulated with tTG treated PTG. A T cell line was cloned and clones tested for stimulation and IFN-gamma production in response to G4 and its analogues.

RESULTS

Some high activity clones were isolated with, for example, a stimulation index (SI) of 15 to G4 and secreting 327 pg/ml of IFN-gamma. Substitution of amino acids at several positions abolished or downregulated stimulation and IFN-gamma production.

CONCLUSIONS

Peptide G4 is highly immunogenic. Certain amino acid substitutions in peptide G4 abolish T cell reactivity while others are partial agonists which may have potential in immunomodulation in this condition.

Mouse pelota gene (Pelo): cDNA cloning, genomic structure, and chromosomal localization

The pelota gene of Drosophila melanogaster encodes a protein which is included in cell cycle regulation. Mutations were found to result in spermatogenic arrest, female sterility and disturbances in the patterning of the eye. We have recently isolated and characterized cDNA clones coding for the human pelota gene (PELO). Here we describe the cloning of the murine pelota cDNA and gene (Pelo) that encodes a 385-amino-acid protein. The exon-intron structure of the gene, which contains three exons, was determined. Comparison of the mouse amino acid sequences with the human and Drosophila sequences revealed an overall high identity (96% and 70%, respectively). Northern blot analysis detected a 1.7-kb transcript in all tissues studied. Southern blot analyses revealed that the pelota gene is present as a single copy in the mouse genome. The mouse pelota gene (Pelo) was mapped to the distal end of chromosome 13, in a region that is homologous with a segment of human chromosome 5q11 containing the orthologous human gene. Cloning of the mouse gene is an important step to study the function of the pelota gene in mammals and to create a mouse model for this evolutionarily conserved gene.

The Caenorhabditis elegans ortholog of human PHF5a shows a muscle-specific expression domain and is essential for C. elegans morphogenetic development

We have recently described a novel human and murine multigene-family that is highly conserved during evolution and shows a PHD-finger-like domain present in the deduced protein sequences. Here, we describe the cloning and characterization of the Caenorhabditis elegans ortholog of human PHF5a. Transgenic phf-5::yfp-reporter techniques in C. elegans identified temporal C. elegans phf-5 expression being restricted to late C. elegans development. The phf-5::yfp expression starts within the morphogenetic phase of embryonic development and lasts to the stage of adult worms. Spatial phf-5 expression is muscle-specific with an expression in the developing pharynx, in body wall muscular structures, and in the anal muscles. By phf-5 RNAi we further demonstrated that PHF-5 is essential in the morphogenetic phase of C. elegans embryonic development as well as in young larvae. In contrast, phf-5 RNAi does not show an evident phenotype to adult worms. Taken together, this is the first report providing evidence for a tissue and stage-specific expression of a PHF5a ortholog, named phf-5, in C. elegans while our data further suggest an essential role of the encoded PHF-5 protein in morphogenetic development and muscle function.

The murine BTB/POZ zinc finger gene Znf131: predominant expression in the developing central nervous system, in adult brain, testis, and thymus

The Znf131/ZNF131 protein belongs to the superfamily of POK proteins containing a BTB/POZ domain in its N-terminal part and 5 typical C2H2 zinc fingers and an additional C2HC zinc finger structure in its C-terminal region. In mouse and human two alternatively spliced transcripts are expressed from the Znf131/ZNF131 gene, resulting from intraexonic splicing. While the longer transcript encodes for three double zinc finger structures the shorter transcript lacks the region coding for the first zinc finger. Although the murine Znf131 gene is ubiquitously expressed, expression analysis applying whole mount in situ hybridization showed a predominant expression in the developing central nervous system with strongest signals in the forebrain, midbrain, and hindbrain areas and in the neural tube. Further dominant expression was seen in embryonic limb buds. In human adult tissues a predominant expression of ZNF131 was seen in different brain areas, i.e., the occipital and temporal lobe, the nucleus caudatus, hippocampus, and the cerebellum as well as in testis and thymus. Therefore, it is possible that Znf131/ZNF131 plays a role during development and organogenesis as well as in the function of the adult central nervous system.

Mutation analysis of the spastin gene (SPG4) in patients in Germany with autosomal dominant hereditary spastic paraplegia

Hereditary spastic paraplegias (HSP) comprise a genetically and clinically heterogeneous group of neurodegenerative disorders characterized by progressive spasticity and hyperreflexia of the lower limbs. Autosomal dominant hereditary spastic paraplegia 4 linked to chromosome 2p (SPG4) is the most common form of autosomal dominant hereditary spastic paraplegia. It is caused by mutations in the SPG4 gene encoding spastin, a member of the AAA protein family of ATPases. In this study the spastin gene of HSP patients from 161 apparently unrelated families in Germany was analyzed. The authors identified mutations in 27 out of the 161 HSP families; 23 of these mutations have not been described before and only one mutation was found in two families. Among the detected mutations are 14 frameshift, four nonsense, and four missense mutations, one large deletion spanning several exons, as well as four mutations that affect splicing. Most of the novel mutations are located in the conserved AAA cassette-encoding region of the spastin gene. The relative frequency of spastin gene mutations in an unselected group of German HSP patients is approximately 17%. Frameshift mutations account for the majority of SPG4 mutations in this population. The proportion of splice mutations is considerably lower than reported elsewhere.

Identification and characterization of a novel murine multigene family containing a PHD-finger-like motif

The genes Phf5a and Phf5b-ps are the first two members of a novel murine multigene family that is highly conserved during evolution and belongs to the superfamily of PHD-finger genes. The Phf5 gene family contains an active locus on mouse chromosome 15, region E and several processed pseudogenes on different chromosomes. The active locus, Phf5a, is expressed ubiquitously in pre- and postnatal murine tissues and encodes a protein of 110 amino acids. The protein is localized in the nucleus in a non-homogenous pattern as the nucleolar subcompartment is almost free of Phf5a. The molecular and biological functions of Phf5a are unknown up-to-date, but the systematic deletion of its yeast homolog is lethal, pointing out that the protein is required for cell viability. Interpretation of our data and review of the literature suggest both basic and essential cellular functions of the Phf5a protein, possibly acting as a chromatin-associated protein.

Influence of mutation type and location on phenotype in 123 patients with Rett syndrome

Rett syndrome (RTT) is a neurodevelopmental disorder that almost exclusively affects girls. It is caused by mutations in the MECP2 gene that encodes the methyl-CpG-binding protein 2 (MeCP2). In this study we correlated mutation type and location with the severity of the phenotype in 123 girls with RTT. The ability to sit, walk, speak, hand function, head growth, occurrence of epilepsy and a combined severity score were assessed in all girls at 5 years of age and then statistically correlated with the results of the molecular genetic tests. We found that patients who carry either missense mutations or deletions located within the hotspot for deletions, an area between the base pairs (bp) 1030 and 1207 of the MECP2 gene, present with a milder phenotype than other patients. We correlated the location of the mutations with the phenotype and found that all mutations that lead to either a complete or partial truncation of the region coding for the nuclear localisation signal (NLS) are associated with a more severe phenotype than other truncating mutations (p = 0.001). We did not find a significant difference between the patients with mutations in the methyl-CpG-binding domain (MBD) and those with mutations in the transcriptional repression domain (TRD). We conclude that mutation type and location correlate with the phenotype in Rett syndrome. All mutations that impair the nuclear localisation signal (NLS) are associated with more severe phenotypes.

Cytogenetic characterization of the TM4 mouse Sertoli cell line. I. Conventional banding techniques, FISH and SKY

Permanent Sertoli cell lines provide an ideal system for the in vitro analysis of function and responsiveness to biochemical/hormonal factors of this particular cell type. In general, cytogenetic analyses of cell lines often reveal remarkable chromosomal changes that may be associated with functional characteristics. In the present study we investigated the mouse Sertoli cell line TM4 by C-banding, silver staining, FISH and spectral karyotyping (SKY). A highly increased chromosome number (average 85-95) as well as five stable marker chromosomes were detected by the conventional staining techniques. SKY identified the markers as a translocation chromosome T(1;3), isochromosomes 11 and 18 and two different-sized microchromosomes. The results show the usefulness of combining SKY and conventional banding methods for the evaluation of chromosome alterations in widely used cell lines.

Targeted expression of SV40 large tumour antigen (TAg) induces a transient enhancement of spermatocyte proliferation and apoptosis

In an attempt to determine the susceptibility of spermatocytes to malignant transformation by simian virus 40 (SV40) large tumour antigen (TAg), transgenic mice harbouring a chimeric gene composed of the SV40 TAg gene fused to the 1.4 kb promoter sequence of the human phosphoglycerate kinase 2 (PGK2) gene were generated. Northern blot analysis on RNA from different tissues indicated a specific transcription of TAg in the testis of PGK2-TAg transgenic mice. Reverse transcription-polymerase chain reaction and Western blot analysis on testes at different stages of development revealed that transcription and translation of the TAg gene starts in 12-day-old testis, which coincides with the appearance of pre-leptotene spermatocytes. Germ cells of transgenic mice showed no tendency toward transformation, but in testes of both 18- and 25-day-old transgenic mice, a significantly enhanced number of spermatocytes was found. In contrast, in 42-day-old transgenic mice no differences in the number of spermatocytes and spermatids were observed. The number of Sertoli cells was determined to be equal in transgenic and wild type mice. In-situ end labelling of fragmented DNA revealed a higher rate of apoptosis in testes of 18-day-old transgenic mice as compared with wild type mice. These results indicate that germ cell homeostasis in transgenic mice is maintained by an apoptotic mechanism.

A 74-bp promoter of the Tnp2 gene confers testis- and spermatid-specific expression in transgenic mice

During the final stages of spermatogenesis, round spermatids undergo several morphological, biochemical, and physiological modifications which result in the formation of mature spermatozoa. One of these is the nuclear condensation, achieved by the replacement of somatic-type and testis-specific histones by transition proteins and protamines leading to cessation of transcription several days before the completion of spermiogenesis. Therefore, a strict temporal and stage-specific gene expression is necessary for the correct differentiation of round spermatids into mature spermatozoa. In this study, the 5' regulatory region of rat Tnp2 gene was investigated by primer extension analysis and transgenic mice study. Primer extension analysis revealed a transcription start site which lies 70 bp upstream of the translation start codon. By transgenic mice studies, we demonstrated that a 147-bp 5' untranslated region corresponding to the region -74 to +73 is sufficient to confer testis- and spermatid-specific expression of rat Tnp2 gene.

Interactions between mouse ZP2 glycoprotein and proacrosin; a mechanism for secondary binding of sperm to the zona pellucida during fertilization

The mouse zona pellucida glycoprotein, mZP2, is thought to be the secondary receptor on eggs for retention of acrosome-reacted sperm during fertilization. Here, we present evidence that one of its complementary binding proteins on sperm is proacrosin/acrosin. mZP2 binds to proacrosin null sperm considerably less effectively than to wild-type sperm. Binding is mediated by a strong ionic interaction between polysulphate groups on mZP2 and basic residues on an internal proacrosin peptide. The stereochemistry of both sulphate groups and basic amino acids determines the specificity of binding. Structurally relevant sulphated polymers and suramin, a polysulphonated anticancer drug, compete with mZP2 for complementary binding sites on proacrosin/acrosin in solid-phase binding assays. The same competitors also displace attached sperm from the zona pellucida of eggs in an in vitro fertilization system. This combination of genetic, biochemical and functional data supports the hypothesis that mZP2-proacrosin interactions are important for retention of acrosome-reacted sperm on the egg surface during fertilization. Safe mimetics of suramin have potential as non-steroidal antifertility agents.

Disruption of an inner arm dynein heavy chain gene results in asthenozoospermia and reduced ciliary beat frequency

Impaired ciliary and flagellar functions resulting in male infertility and recurrent respiratory tract infections are found in patients suffering from primary ciliary dyskinesia (PCD). In most cases, axonemal defects are present, i.e. PCD patients often lack inner and/or outer dynein arms in their sperm tails and cilia, supporting the hypothesis that mutations in dynein genes may cause PCD. However, to date it is unclear whether mutations in dynein heavy chain genes are responsible for impaired flagellar and ciliary motility in mammals. To elucidate the role of the mouse dynein heavy chain 7 (MDHC7) gene, which encodes a component of the inner dynein arm, we have generated mice lacking this dynein heavy chain isoform. Both MDHC7(+/-) and MDHC7(-/-) mice are viable and show no malformations; however, homozygous males produce no offspring. In comparison to MDHC7(+/-) and wild-type mice the spermatozoa of MDHC7(-/-) mice revealed a dramatic reduced straight line velocity and progressive movement, resulting in the inability of MDHC7-deficient sperm to move from the uterus into the oviduct. Additionally, we measured the beat frequency of tracheal cilia and observed a decrease in the beat frequency of approximately 50% in MDHC7(-/-) mice. The reduction in both ciliary and flagellar motility is not correlated with any gross defects in the axonemal structure. The phenotype of MDHC7(-/-) mice is similar to that observed in some patients suffering from PCD, and our data strongly suggest that in some patients this disease could be due to mutations in the homologous human gene DNAH1 (HDHC7).

In vivo studies on the metabolism of the monoterpenes S-(+)- and R-(-)-carvone in humans using the metabolism of ingestion-correlated amounts (MICA) approach

The major in vivo metabolites of S-(+)- and R-(-)-carvone in a metabolism of ingestion correlated amounts (MICA) experiment were newly identified as alpha,4-dimethyl-5-oxo-3-cyclohexene-1-acetic acid (dihydrocarvonic acid), alpha-methylene-4-methyl-5-oxo-3-cyclohexene-1-acetic acid (carvonic acid), and 5-(1,2-dihydroxy-1-methylethyl)-2-methyl-2-cyclohexen-1-one (uroterpenolone) on the basis of mass spectral analysis in combination with syntheses and NMR experiments. Minor metabolites were identified as reduction products of carvone, namely, the alcohols carveol and dihydrocarveol. The previously identified major in vivo metabolite in rabbits, 10-hydroxycarvone, could not be detected, indicating either concentration effects or interspecies differences. Metabolic pathways for carvone in humans including oxidation of the double bond in the side chain and, to a minor extent 1,2- and 1,4 + 1,2-reduction of carvone, are discussed. No differences in metabolism between S-(+)- and R-(-)-carvone were detected.

Human cyritestin genes (CYRN1 and CYRN2) are non-functional

The mouse cyritestin gene is a member of the ADAM (a disintegrin and metalloprotease) gene family and codes for a membrane-anchored sperm protein. Recently, it was shown that cyritestin is critical for male fertility in the mouse. Spermatozoa of cyritestin-deficient mice are not able to bind to the zona pellucida of the oocyte and therefore unable to fertilize the egg. However, zona-free oocytes can be fertilized and the resulting embryos show normal development. In contrast to the mouse, where only one gene for cyritestin (Cyrn) is reported, two cyritestin genes (CYRN1 and CYRN2) are known in humans. The human CYRN1 and CYRN2 genes are located on chromosomes 8 and 16, respectively. We report that 27% of fertile men are deficient for the CYRN1 gene but that all have a CYRN2 gene, suggesting that the CYRN2 gene is the orthologous mouse cyritestin gene in humans and might be involved in sperm-egg interactions. However, the characterization of CYRN2 transcripts from testicular RNA of CYRN1-deficient men demonstrated many termination codons in the synthesized cyritestin cDNA. Furthermore, Western-blot analysis with human testicular protein extracts using an anti-cyritestin antibody failed to detect any cyritestin protein. These results demonstrate clearly that both cyritestin genes are non-functional in humans.

Assessment of promoter elements of the germ cell-specific proacrosin gene

The testis-specific proacrosin gene encodes for a fertilization-promoting protein. In mouse and rat it is first transcribed in late pachytene spermatocytes and revealed to be translationally regulated. Former proacrosin promoter studies demonstrated that elements necessary for conducting a stage and temporal-specific expression of the gene are located within 0.9 kb upstream of the translational start codon. In the present study we analyzed putative cis-acting elements located in this promoter region for their specific binding properties to nuclear factors assumed to be involved in proacrosin gene regulation. Supplement of specific antibodies in electrophoretic mobility shift assays (EMSA) revealed that two Y-box proteins and the transcription factors CREM and YY1 interact with proacrosin promoter elements. The Y-box proteins, antigenically related to the frog Y-box proteins FRGY1 and FRGY2, bound to the Y-box (55-66 bp upstream of the ATG initiation codon) in brain and testis nuclear extracts, respectively. CREM bound to three elements (30-37, 252-259, and 717-724 bp upstream of ATG). The ubiquitous transcription factor YY1 bound to a conserved element in the central proacrosin promoter (457-473 bp upstream of ATG) and showed almost germ cell-specific truncates in EMSA. These results suggest that the identified factors are involved in proacrosin gene regulation.

Teratozoospermia in mice lacking the transition protein 2 (Tnp2)

It is believed that the transition proteins (Tnp1 and Tnp2) participate in the removal of the nucleohistones and in the initial condensation of the spermatid nucleus. Later in spermatogenesis, Tnp1 and Tnp2 are replaced by the protamines 1 and 2. In an effort to elucidate the physiological role of Tnp2, we have disrupted its locus by homologous recombination. Breeding of the Tnp2(-/-) males on different genetic backgrounds revealed normal fertility on the mixed background C57BL/6Jx129/Sv, but total infertility on the inbred 129/Sv background. Light and electron microscopy showed that the germ cells were capable of undergoing chromatin condensation, although many spermatozoa exhibited head abnormalities with acrosomes not attached to the nuclear envelope. Furthermore, migration of Tnp2(-/-) spermatozoa from the uterus into the oviduct was reduced. These results suggest that male infertility of the Tnp2(-/-) mice is a result of sperm head abnormalities and reduced sperm motility. The increased level of the Tnp1 transcript in testes of the Tnp2-deficient mice raises the possibility that a deficiency created through the disruption of the Tnp2 gene can be compensated for by recruitment of the Tnp1.

Cloning, organisation, chromosomal localization and expression analysis of the mouse Prkag1 gene

The mammalian 5'-AMP-activated protein kinase (AMPK) is a heterotrimeric protein consisting of alpha-, beta- and gamma-subunits. The alpha-subunit is the catalytic subunit. The non-catalytic subunits AMPK-beta and AMPK-gamma form, together with the catalytic AMPK-alpha, the active kinase complex in mammals and its homologue in yeast. The gene for AMPK-gamma-1 has been designated recently as PRKAG1. We have isolated mouse Prkag1 cDNA from testis (1623 nt) coding for 330 aa and we have shown its ubiquitous expression as a 1.8-kb transcript. A comparison between mouse, rat and human PRKAG1 cDNA and protein sequences shows that the gene is highly conserved among these species with a homology of 96% at the protein level. Southern blot analysis indicates that there is more than one gene for PRKAG in the mouse genome. Prkag1 contains 12 exons with short introns. Analysis of 50 interspecific backcross mice mapped the mouse gene to the distal region of chromosome 15.

Mice deficient for spermatid perinuclear RNA-binding protein show neurologic, spermatogenic, and sperm morphological abnormalities

Spermatid perinuclear RNA-binding protein (SPNR) is a microtubule-associated RNA-binding protein that localizes to the manchette in developing spermatids. The Spnr mRNA is expressed at high levels in testis, ovary, and brain and is present in these tissues in multiple forms. We have generated a gene trap allele of the murine Spnr, named Spnr(+/GT). Spnr(GT/GT) mutants show a high rate of mortality, reduced weight, and an abnormal clutching reflex. In addition to minor anatomical abnormalities in the brain, males exhibit defects in spermatogenesis that include a thin seminiferous epithelium and disorganization of spermatogenesis. Most of the sperm from mutant males display defects in the flagellum and consequently show decreased motility and transport within the oviducts. Furthermore, sperm from mutant males achieve in vitro fertilization less frequently. Our findings suggest that SPNR plays an important role in normal spermatogenesis and sperm function. Thus, the Spnr(GT/GT) mutant male mouse provides a unique model for some human male infertility cases.

MECP2 mutations in sporadic cases of Rett syndrome are almost exclusively of paternal origin

Rett syndrome (RTT) is an X-linked neurodevelopmental disorder that apparently is lethal in male embryos. RTT almost exclusively affects female offspring and, in 99.5% of all cases, is sporadic and due to de novo mutations in the MECP2 gene. Familial cases of RTT are rare and are due to X-chromosomal inheritance from a carrier mother. We analyzed the parental origin of MECP2 mutations in sporadic cases of RTT, by analysis of linkage between the mutation in the MECP2 gene and intronic polymorphisms in 27 families with 15 different mutations, and we found a high predominance of mutations of paternal origin in 26 of 27 cases (P<.001). The paternal origin was independent of type of mutation and was found for single-base exchanges as well as for deletions. Parents were not of especially advanced age. We conclude that de novo mutations in RTT occur almost exclusively on the paternally derived X chromosome and that this is most probably the cause for the high female:male ratio observed in patients with RTT. Affected males recently have been described in a few cases of familial inheritance. Identification of the parental origin may be useful to distinguish between the sporadic form of RTT and a potentially familial form. This distinction will allow geneticists to offer more-specific counseling and discriminate between higher (maternal origin) and lower (paternal origin) recurrence risk.