High frequency of DAZ1/DAZ2 gene deletions in patients with severe oligozoospermia

Deletions of the DAZ gene family in distal Yq11 are always associated with deletions of the azoospermia factor c (AZFc) region, which we now estimate extends to 4.94 Mb. Because more Y gene families are located in this chromosomal region, and are expressed like the DAZ gene family only in the male germ line, the testicular pathology associated with complete AZFc deletions cannot predict the functional contribution of the DAZ gene family to human spermatogenesis. We therefore established a DAZ gene copy specific deletion analysis based on the DAZ-BAC sequences in GenBank. It includes the deletion analysis of eight DAZ-DNA PCR markers [six DAZ-single nucleotide varients (SNVs) and two DAZ-sequence tag sites (STS)] selected from the 5' to the 3'end of each DAZ gene and a deletion analysis of the gene copy specific EcoRV and TaqI restriction fragments identified in the internal repetitive DAZ gene regions (DYS1 locus). With these diagnostic tools, 63 DNA samples from men with idiopathic oligozoospermia and 107 DNA samples from men with proven fertility were analysed for the presence of the complete DAZ gene locus, encompassing the four DAZ gene copies. In five oligozoospermic patients, we found a DAZ-SNV/STS and DYS1/EcoRV and TaqI fragment deletion pattern indicative for deletion of the DAZ1 and DAZ2 gene copies; one of these deletions could be identified as a 'de-novo' deletion because it was absent in the DAZ locus of the patient's father. The same DAZ deletions were not found in any of the 107 fertile control samples. We therefore conclude that the deletion of the DAZ1/DAZ2 gene doublet in five out of our 63 oligozoospermic patients (8%) is responsible for the patients' reduced sperm numbers. It is most likely caused by intrachromosomal recombination events between two long repetitive sequence blocks (AZFc-Rep1) flanking the DAZ gene structures.     

Divergent roles of the DEAD-box protein BS-PL10, the urochordate homologue of human DDX3 and DDX3Y proteins, in colony astogeny and ontogeny.

Proteins of the highly conserved PL-10 (Ded1P) subfamily of DEAD-box family, participate in a wide variety of biological functions. However, the entire spectrum of their functions in both vertebrates and invertebrates is still unknown. Here, we isolated the Botryllus schlosseri (Urochordata) homologue, BS-PL10, revealing its distributions and functions in ontogeny and colony astogeny. In botryllid ascidians, the colony grows by increasing the number of modular units (each called a zooid) through a whole colony synchronized and weekly cyclical astogenic budding process (blastogenesis). At the level of the colony, both BS-PL10 mRNA and its protein (78 kDa) fluctuate in a weekly pattern that corresponds with the animal's blastogenic cycle, increasing from blastogenic stage A to blastogenic stage D. At the organ/module level, a sharp decline is revealed. Primary and secondary developing buds express high levels of BS-PL10 mRNA and protein at all blastogeneic stages. These levels are reduced four to nine times in the new set of functional zooids. This portrait of colony astogeny differed from its ontogeny. Oocytes and sperm cells express high levels of BS-PL10 protein only at early stages of development. Young embryos reveal background levels with increased expressions in some organs at more developed stages. Results reveal that higher levels of BS-PL10 mRNA and protein are characteristic to multipotent soma and germ cells, but patterns deviate between two populations of differentiating stem cells, the stem cells involved in weekly blastogenesis and stem cells involved in embryogenesis. Two types of experimental manipulations, zooidectomy and siRNA assays, have confirmed the importance of BS-PL10 for cell differentiation and organogenesis. BS-PL10 (phylogenetically matching the animal's position in the evolutionary tree), is the only member of this subfamily in B. schlosseri, featuring a wide range of biological activities, some of which represent pivotal roles. The surprising weekly cyclical expression and the participation in cell differentiation posit this molecule as a model system for studying PL10 protein subfamily.     

特发性无精子症和严重少精子症患者DAZ基因缺失的分析

目的　评估特发性无精子症和严重少精子症患者Y染色体上DAZ基因缺失的发生情况。方法　采用聚合酶链反应技术 (PCR)扩增 33例特发性无精子症和严重少精子症患者DAZ基因中的 4个序列标记位点SY15 4、SY2 5 4、SY2 5 5和SY15 5。 5 0例生育男性为阳性对照组 ,5例女性为阴性对照组。结果　 33例特发性无精子症和严重少精子症患者DAZ基因缺失率为 15 2 % ,其中 2 6例特发性无精子症患者有 4例缺失 (15 4 % ) ,1例染色体核型为 4 7,XXY ;7例特发性严重少精子症患者中有 1例缺失 (14 3% )。 4个序列标记位点在阳性对照组中均有条带扩增 ,在阴性对照组中未见条带扩增。结论　特发性无精子症和严重少精子症患者均存在DAZ基因缺失 ,特发性无精子症患者缺失率高于特发性严重少精子症患者 ,与国外报道相一致。聚合酶链反应扩增DAZ基因位点是筛选Y染色体缺失的有效方法。     

RBMY, a probable human spermatogenesis factor, and other hnRNP G proteins interact with Tra2beta and affect splicing

The RBMY gene family is found on the Y chromosome of all mammals, and microdeletions are strongly associated with infertility in men. RBMY expresses RBM only in the nuclei of germ cells, whereas its X chromosome homologue, RBMX, expresses hnRNP G ubiquitously. We show here that RBM, hnRNP G and a novel testis-specific relative, termed hnRNP G-T, interact with Tra2beta, an activator of pre-mRNA splicing that is ubiquitous but highly expressed in testis. Endogenous hnRNP G and Tra2beta proteins are associated in HeLa nuclear extracts. RBM and Tra2beta co-localize in two major domains in human spermatocyte nuclei. Phosphorylation enhanced the interaction and reduced competing RNA binding to the interaction domains. Incubation with the protein interaction domain of RBM inhibited splicing in vitro of a specific pre-mRNA substrate containing an essential enhancer bound by Tra2beta. The RNA-binding domain of RBM affected 5' splice site selection. We conclude that the hnRNP G family of proteins is involved in pre-mRNA splicing and infer that RBM may be involved in Tra2beta-dependent splicing in spermatocytes.     

In vitro immune functions in patients with minor, moderate, and severe kidney impairment

We examined the in vitro immune response of lymphocytes from 86 non-dialyzed patients with progressive renal failure and 48 healthy control subjects by comparing the production of interleukin-2, the mitogen-induced proliferative response and sensitivity to glucocorticoid of lymphocyte cultures. The patients were divided in three groups with minor, moderate, and severe uremia. The uremic lymphocyte responses to stimulation with concanavalin A (Con A) were significantly lower than those of control lymphocyte cultures. A similar but not significant decrease was also seen in phytohemagglutinin (PHA) and pokeweed mitogen stimulated cultures. There was no trend towards diminishing mitogen responses with decreasing renal function. The median interleukin-2 activity in the uremic cell cultures was decreased by 50% during the culture period but the decrease was not significant. However, PHA and Con A stimulated lymphocyte cultures from all groups of patients were significantly more sensitive to the immunosuppressive effect of methylprednisolone. Thus an increased sensitivity to the immunosuppressive effect of glucocorticoid can be demonstrated in vitro at an early stage of progressive renal disease.     

Quantification of MYCN, DDX1, and NAG gene copy number in neuroblastoma using a real-time quantitative PCR assay.

Amplification of the proto-oncogene MYCN is a strong adverse prognostic factor in neuroblastoma patients in all tumor stages. The status of the MYCN gene has become an important factor in clinical decision making and therapy stratification. Consequently, fast and accurate assessment of MYCN gene copy number is of the utmost importance and the use of two independent methods to determine MYCN status is recommended. For these reasons we have developed and evaluated a real-time quantitative PCR (Q-PCR) assay as an alternative for time-consuming Southern blot analysis (SB), and as a second independent technique in parallel with fluorescence in situ hybridization (FISH) analysis. Advantages of Q-PCR are a large dynamic range of quantification, no requirement for post-PCR sample handling and the need for very small amounts of starting material. The accuracy of the assay was illustrated by measurement of MYCN single gene copy changes in DNA samples of two patients with 2p deletion and duplication, respectively. Two different detection chemistries i.e., a sequence specific TaqMan probe and a generic DNA binding dye SYBR Green I were evaluated and shown to yield similar results. Also, two different calculation methods for copy number determination were used i.e., the kinetic method and the comparative C(T) method, and shown to be equivalent. In total, 175 neuroblastoma samples with known MYCN status, as determined by FISH and/or SB, were examined. Q-PCR data were highly concordant with FISH and SB data. In addition to MYCN copy number evaluation, DDX1 and NAG gene copy numbers were determined using a similar Q-PCR strategy. Survival analysis pointed out that DDX1 and/or NAG amplification has no additional adverse effect on prognosis.     

The human Y chromosome genes BPY2, CDY1 and DAZ are not essential for sustained fertility

Deletions of the AZFc interval of the human Y chromosome are found in >5% of male patients with idiopathic infertility and are associated with a severely reduced sperm count. The most common deletion type is large (>1 Mb) and removes members of the Y-borne testis-specific gene families of BPY2, CDY1, DAZ, PRY, RBMY2 and TTY2, which are candidate AZF genes. Four exceptional individuals who have transmitted a large AZFc deletion naturally to their infertile sons have, however, been described. In three cases, transmission was to an only son, but in the fourth case a Y chromosome, shown to be deleted for all copies of DAZ, was transmitted from a father to his four infertile sons. Here we present a second family of this latter type and demonstrate that an AZFc-deleted Y chromosome lacking not only DAZ, but also BPY2 and CDY1, has been transmitted from a father to his three infertile sons. Polymerase chain reaction (PCR) and Southern blot analyses revealed no difference in the size of the AZFc deletion in the father and his sons. We propose that the father carries rare alleles of autosomal or X-linked loci which suppress the infertility that is frequently associated with the absence of AZFc.     

AZFc区gr/gr及DAZ基因拷贝缺失与原发性男性生精障碍的相关性研究

目的探讨Y染色体AZFc区gr/gr缺失及DAZ基因拷贝缺失与男性生精障碍的相关性。方法运用PCR与PCR-RFLP检测技术,对252例正常生精男性,430例原发性生精障碍男性患者进行Y染色体AZFc区gr/gr缺失及DAZ基因拷贝缺失分析。结果正常生精男性组gr/gr缺失率为5.2%,原发性生精障碍组gr/gr缺失率为10.2%,P=0.021,差异有统计学意义;正常生精男性组DAZ1/DAZ2基因拷贝共缺失率为2.0%,原发性生精障碍组中DAZ1/DAZ2基因拷贝共缺失率为7.0%,P=0.004,差异亦有统计学意义;正常生精男性组DAZ3/DAZ4基因拷贝共缺失率为3.2%,在生精障碍组中DAZ3/DAZ4基因拷贝的共缺失率为3.3%,P=0.954,差异无统计学意义。结论在原发性男性生精障碍患者中存在较高频率的gr/gr缺失及DAZ1/DAZ2基因共缺失,提示gr/gr缺失及DAZ1/DAZ2基因拷贝的共缺失是男性不育的高风险因子。     

Evolution of the DAZ gene family suggests that Y-linked DAZ plays little, or a limited, role in spermatogenesis but underlines a recent African origin for human populations

The recent transposition to the Y chromosome of the autosomal DAZL1 gene, potentially involved in germ cell development, created a unique opportunity to study the rate of Y chromosome evolution and assess the selective forces that may act upon such genes, and provided a new estimate of the male-to-female mutation rate (alpham). Two different Y- located DAZ sequences were observed in all Old World monkeys, apes and humans. Different DAZ copies originate from independent amplification events in each primate lineage. A comparison of autosomal DAZL1 and Y- linked DAZ intron sequences gave a new figure for male-to-female mutation rates of alpham = 4. It was found that human DAZ exons and introns are evolving at the same rate, implying neutral genetic drift and the absence of any functional selective pressures. We therefore hypothesize that Y-linked DAZ plays little, or a limited, role in human spermatogenesis. The two copies of DAZ in man appear to be due to a relatively recent duplication event (55 000-200 000 years). A worldwide survey of 67 men from five continents representing 19 distinct populations showed that most males have both DAZ variants. This implies a common origin for the Y chromosome consistent with a recent 'out of Africa' origin of the human race.      

Cognitive assessment of geriatric schizophrenic patients with severe impairment.

There is evidence that some elderly patients with chronic schizophrenia experience marked impairments in cognitive functioning. Assessment of these patients may be difficult with traditional neuropsychological measures. The purpose of the present study was to determine if cognitive functioning could be validly assessed with the Alzheimer's Disease Assessment Scale-Late Version Cognitive factor score (ADAS-L Cog) in patients whose scores on the Mini-Mental State Examination (MMSE) reflect profound cognitive impairment. Patients with MMSE scores from 0 to 10 were selected from a larger database. Neuropsychological instruments designed for the assessment of mild to moderate dementia were found to be inadequate in this profoundly impaired population, due to floor effects. In contrast, there was a significant relationship between ADAS-L scores and several criterion measures, including the MMSE (R=-.71, P<.001), the Social Adaptive Functions Evaluation (SAFE) social functions scale (R=.47, P<.001), and the negative symptom total score of the Positive and Negative Syndrome Scale (PANSS) (R=.412, P<.001). The MMSE was somewhat less strongly correlated with both social functions (R=-.401, P<.001) and the negative symptom total score of the PANSS (R=-.366, P<.001). These results suggest that cognition can be reliably and validly assessed with instruments such as the ADAS-L that are designed for the assessment of severely impaired patients.     

DDX1, DDX21, and DHX36 helicases form a complex with the adaptor molecule TRIF to sense dsRNA in dendritic cells

The innate immune system detects viral infection predominantly by sensing viral nucleic acids. We report?the identification of a viral sensor, consisting of RNA helicases DDX1, DDX21, and DHX36, and the adaptor molecule TRIF, by isolation and sequencing of poly I:C-binding proteins in myeloid dendritic cells?(mDCs). Knockdown of each helicase or TRIF by shRNA blocked the ability of mDCs to mount type?I interferon (IFN) and cytokine responses to poly I:C,?influenza A virus, and reovirus. Although DDX1 bound poly I:C via its Helicase A domain, DHX36 and DDX21 bound the TIR domain of TRIF via their HA2-DUF and PRK domains, respectively. This sensor was localized within the cytosol, independent of the endosomes. Thus, the DDX1-DDX21-DHX36 complex represents a dsRNA sensor that uses the TRIF pathway to activate type I IFN responses in the cytosol of mDCs.     

DDX3和DDX5在环磷酰胺致大鼠神经管畸形神经上皮细胞中的表达变化

目的:探讨RNA解旋酶DDX3和DDX5在环磷酰胺致大鼠神经管畸形神经上皮细胞中的表达及与神经管畸形发生之间的关系,为阐明神经管畸形发生的分子机制提供实验依据。方法:选取不同时间点环磷酰胺致神经管畸形模型组和对照组大鼠石蜡切片,应用免疫荧光组织化学显色法检测神经上皮细胞中DDX3和DDX5的表达变化。结果:与对照组相比,模型组大鼠神经管神经上皮细胞中DDX3和DDX5阳性表达在环磷酸胺处理后4 h无改变,8、12、24 h均升高,48 h则降低,差异均有统计学意义。结论:环磷酰胺导致大鼠胚胎神经管神经上皮细胞中DDX3和DDX5表达异常,提示DDX3和DDX5可能参与了神经管畸形的发生。     

810例严重少(无)精子症患者Y染色体微缺失筛查与分析

目的筛查原发无精子症与重度少精子症患者Y染色体微缺失情况,探讨Y染色体微缺失与男性不育的关系。方法采用改良多重PCR方法对810例男性不育患者(457例原发无精子症和353例严重少精子症)基因组DNA进行Y染色体微缺失筛查。结果810例患者中发现77例Y染色体微缺失患者,缺失率为9.5%,其中少精子症31例,均为AZFc微缺失,无精子症46例,缺失类型呈多样化。缺失类型包括AZFa微缺失3例(3.90%),AZFb微缺失2例(2.60%),AZFc微缺失63例(81.82%),AZFb+c微缺失4例(5.19%),AZFa+b+c微缺失5例(6.49%)。结论Y染色体微缺失是原发无精子症和少精子症的重要原因之一,AZFc缺失为最常见的缺失类型,对此类患者进行Y染色体微缺失的常规筛查是有必要的,尤其是拟行辅助生殖技术助孕的不育患者。     

Mutations in PHD-like domain of the ATRX gene correlate with severe psychomotor impairment and severe urogenital abnormalities in patients with ATRX syndrome

Mutations in ATRX are associated with a wide and clinically heterogeneous spectrum of X-linked mental retardation syndromes. The ATRX protein, involved in chromatin remodelling, belongs to the family of SWI/SNF DNA helicases and contains a plant homeodomain (PHD)-like domain. To date, more than 60 different mutations have been reported in ATRX. One of them is recurrent and accounts for 20% of all the reported mutations, whereas all others are private. Most mutations are clustered in the two major functional domains, the helicase and the PHD-like domain. So far, no clear genotype-phenotype correlation has been established, with exception to the rare truncating mutations located at the C-terminal part of the protein, which are consistently associated with severe urogenital defects. In this study, we report the molecular analysis performed in 16 families positive for ATRX. Our findings indicate that, in addition to the previously described mutation 'hotspot' in the PHD-like domain, two other protein sections emerge as minor 'hotspots' in the helicase region encoded by exons 18-20 and 26-29, respectively, gathering 33% of all described mutations. Additionally, based on the clinical data collected for 22 patients from the 16 families, we observe that mutations in the PHD-like domain produce severe and permanent psychomotor deficiency, usually preventing patients from walking, as well as constant urogenital abnormalities, while mutations in the helicase domain lead to delayed but correct psychomotor acquisitions together with mild or absent urogenital abnormalities. In summary, mutations in the helicase domain are associated with milder phenotypes than mutations in the PHD-like domain.     

1H MRS in stroke patients with and without cognitive impairment

The pathophysiological basis of cognitive impairment in patients with cerebrovascular disease (CVD) is not well understood, particularly in relation to the role of non-infarction ischemic change and associated Alzheimer-type pathology. We used single voxel 1H MRS to determine the differences in brain neurometabolites in non-infarcted frontal white matter and occipito-parietal gray matter of 48 stroke patients with or without cognitive impairment and 60 elderly controls. The results showed that there were no significant neurometabolite differences between the stroke cohort and healthy elderly controls, but there was a difference in NAA/H2O between the stroke patients that had cognitive impairment (vascular dementia (VaD) and vascular cognitive impairment (VCI)) compared with those patients with no impairment. This was significant in the occipito-parietal gray matter, but not in the frontal white matter, although the results were in the same direction for the latter. This suggests that cognitive impairment in stroke patients may be related to cortical neuronal dysfunction rather than purely subcortical change. Moreover, cortical regions not obviously infarcted may have dysfunctional neurons, the pathophysiological basis for which needs further study.