[Linkage analysis of susceptibility loci in 2 target chromosomes in pedigrees with paranoid schizophrenia and undifferentiated schizophrenia].

OBJECTIVE: To investigate the relationship of susceptibility loci in chromosomes 1q21-25 and 6p21-25 and schizophrenia subtypes in Chinese population. METHODS: A genomic scan and parametric and non-parametric analyses were performed on 242 individuals from 36 schizophrenia pedigrees, including 19 paranoid schizophrenia and 17 undifferentiated schizophrenia pedigrees, from Henan province of China using 5 microsatellite markers in the chromosome region 1q21-25 and 8 microsatellite markers in the chromosome region 6p21-25, which were the candidates of previous studies. All affected subjects were diagnosed and typed according to the criteria of the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revised (DSM-IV-TR; American Psychiatric Association, 2000). All subjects signed informed consent. RESULTS: In chromosome 1, parametric analysis under the dominant inheritance mode of all 36 pedigrees showed that the maximum multi-point heterogeneity Log of odds score method (HLOD) score was 1.33 (α = 0.38). The non-parametric analysis and the single point and multi-point nonparametric linkage (NPL) scores suggested linkage at D1S484, D1S2878, and D1S196. In the 19 paranoid schizophrenias pedigrees, linkage was not observed for any of the 5 markers. In the 17 undifferentiated schizophrenia pedigrees, the multi-point NPL score was 1.60 (P= 0.0367) at D1S484. The single point NPL score was 1.95(P= 0.0145) and the multi-point NPL score was 2.39 (P= 0.0041) at D1S2878. Additionally, the multi-point NPL score was 1.74 (P= 0.0255) at D1S196. These same three loci showed suggestive linkage during the integrative analysis of all 36 pedigrees. In chromosome 6, parametric linkage analysis under the dominant and recessive inheritance and the non-parametric linkage analysis of all 36 pedigrees and the 17 undifferentiated schizophrenia pedigrees, linkage was not observed for any of the 8 markers. In the 19 paranoid schizophrenias pedigrees, parametric analysis showed that under recessive inheritance mode the maximum single-point HLOD score was 1.26 (α = 0.40) and the multi-point HLOD was 1.12 (α = 0.38) at D6S289 in the chromosome 6p23. In nonparametric analysis, the single-point NPL score was 1.52 (P= 0.0402) and the multi-point NPL score was 1.92 (P= 0.0206) at D6S289. CONCLUSION: Susceptibility genes correlated with undifferentiated schizophrenia pedigrees from D1S484, D1S2878, D1S196 loci, and those correlated with paranoid schizophrenia pedigrees from D6S289 locus are likely present in chromosome regions 1q23.3 and 1q24.2, and chromosome region 6p23, respectively.

FBXO7 gene mutations may be rare in Chinese early-onset Parkinsonism patients.

A recent study has shown that FBXO7 is a causative gene for PARK15-linked autosomal recessive early-onset Parkinsonism which was described by Davison for the first time in 1954 and known as Pallido-Pyramidal Disease or Parkinsonia-Pyramidal Syndrome in the past. In order to investigate the characteristics of FBXO7 gene mutations in Chinese early-onset Parkinsonism patients, we performed polymerase chain reaction and DNA direct sequencing on 135 patients and 200 controls. In this study, we found 10 polymorphisms including two novel polymorphisms (-274G-->C, c.A155G), but no pathogenetic mutations in the FBXO7 gene were detected. This suggests that FBXO7 mutations may be rare in Chinese early-onset Parkinsonism patients.

Analysis of SCA2 and SCA3/MJD repeats in Parkinson's disease in mainland China: genetic, clinical, and positron emission tomography findings.

To investigate the prevalence and clinical feature(s) of Parkinson's disease (PD) patients with expanded (ATXN2 and MJD1) genes of spinocerebellar ataxia type 2 and 3 (SCA2 and SCA3/MJD) in a mainland Chinese population, CAG triplet repeat expansions of (SCA2 and SCA3/MJD) genes (ATXN2 and MJD1) were analyzed in a cohort of 452 PD patients, including 386 sporadic and 66 familial forms. Striatal dopamine transporter was evaluated in two SCA2 and two SCA3/MJD-positive family members, an idiopathic PD patient and a healthy control using carbon (C11) [(11)C]-radiolabeled-CFT positron emission tomography (PET). We found two patients in one familial PD (FPD) family (1.5%) and two sporadic PD patients (0.5%) with expanded CAG repeats in the ATXN2 locus, four patients in two FPD families (3%) and another three sporadic PD patients (0.8%) in the MJD1 locus. [(11)C]-CFT PET in detected members in SCA2 and SCA3/MJD families showed decrements of (11)C-CFT uptake. These findings suggest that a mutation in SCA2 or SCA3/MJD may be one of the genetic causes of PD.

[Growing of human embryonic stem cells on feeders derived from themselves].

This study was carried out to determine whether mesenchymal stem cells (MSCs) derived from teratoma of human embryonic stem cells (hESCs) function as feeder cells to support hESCs growth. Approximately 5x10(6) hESCs were injected into the hind limb muscle of each SCID-beige mouse to form teratoma. After 8 weeks, the MSCs were isolated from the teratoma and cultured in Mesencult medium. Purified MSCs were then used as the feeder cells for hESCs culture. High purity MSCs derived from teratoma were isolated. The cells were morphologically similar to bone marrow MSCs (bMSCs). The teratoma-derived MSCs were negative for CD34 and CD45 but positive for CD29, CD49b, CD105, CD73, and CD90, which resembled those expressed by bMSCs. After passaged on MSCs feeder cells more than 10 passages, hESCs maintained hESC characteristics in morphology. Reverse PCR showed the expression of Oct4 and Nanog. SSEA-1 was negative and SSEA-4, TRA-1-60, and TRA-1-81 were positive. Alkaline phosphatase staining showed positive results.The karyotype remained normal. Moreover, the hECSs cultured on teratoma-derived MSCs formed teratoma in vivo and embryoid body in vitro confirmed their pluripotency. Accordingly, MSCs derived from hESCs by in vivo differentiation can be used as the feeder cells for hESCs culture.

Screening of LRRK2 interactants by yeast 2-hybrid analysis.

OBJECTIVE: To isolate and identify the potential binding partners of LRRK2, a gene linked to both dominant familial form and sporadic form of Parkinson's disease, thus to further our knowledge of its function. METHODS: We used a sequence containing full-length of COR domain and part of ROC and MAPKKK domain as bait. The bait amplified by polymerase chain reaction (PCR) was then cloned into a yeast expression plasmid pGBKT7. After being sequenced and analyzed, pGBKT7-bait was transformed into the yeast strain AH109. Western blot was performed to confirm the expression of pGBKT7-bait in AH109 yeast strain. Then human fetal brain cDNA library was transformed into that yeast strain, which could express pGBKT7-bait fusion protein. The yeast strain which contained pGBKT7-bait and human fetal brain cDNA library was plated on quadruple dropout medium (SD/-Trp/-Leu/-His/-Ade) containing X-alpha-gal. We retested these positive colonies using 2 independent yeast strains AH109 contained pGBKT7-bait or pGBKT7, respectively. At last, these plasmids isolated from these true positive colonies were analyzed by bioinformatics. RESULTS: We obtained 9 true positive colonies, these colonies were sequenced, and we performed sequence Blast in GenBank. Three colonies of the 9 positive colonies were not in open reading-frames. Among other 6 colonies, there were known proteins including spermatid perinuclear RNA-binding protein (STRBP) and BCL2-associated athanogene 5 isoform b (BAG5), as well as unknown proteins including tyrosine phosphatase non-receptor type (PTPN23), l(3)mbt-like 3 isoform b (L3MBTL3), RALY RNA binding protein-like isoform 1 (RALYL), and Homo sapiens mRNA for KIAA1783 protein, partial cds (KIAA1783). CONCLUSION: True positive colonies of LRRK2 are successfully obtained by the yeast 2-hybrid. Our screened proteins may provide a new research clue for revealing biological functions of LRRK2, pathogenesis of Parkinson's disease, and other neurodegerations.

Efficient protein expression from the endogenous RNA polymerase I promoter using a human ribosomal DNA targeting vector.

Vector systems to deliver, integrate and express therapeutic genes in host cells are essential for gene therapy. In the present study, we investigated a novel vector system for integration and expression of a transgene. In this system, the transgene expression was driven by an endogenous RNA polymerase I (Pol I) promoter after being integrated into the ribosomal DNA (rDNA) locus. Human coagulation factor IX coding sequence (FIX), with an internal ribosome entry sites element at its leader region, was targeted into the 18S rDNA locus via homologous recombination. FIX protein expression, which was under the control of the endogenous Pol I promoter, was found to be similar to that of a moderate Pol II promoter. The average FIX expression level of the rDNA recombinants was additionally enhanced to that from a strong Pol II promoter as a result of elimination of position effects. Our data suggest the possibility of applying this system in gene therapy for hereditary diseases.

[Biological characteristics and safety evaluation of endothelial progenitor cells from the umbilical cord blood].

OBJECTIVE: To investigate the biological characteristics of endothelial progenitor cells (EPCs) from the umbilical cord blood (UCB), and to evaluate their oncogenicity after long-term culture in vitro. METHODS: The mononuclear cells (MNCs) were isolated from the UCB and cultured in MCDB131 medium supplemented with 20% FBS, VEGF and other growth factors. Morphology of the EPCs was observed, and the growth curve of the EPCs was investigated. Surface antigens of the EPCs were analyzed by the flow-cytometer. The capability of intaking the acetylated low-density lipoprotein (acLDL) of the EPCs was detected using fluoresencent chemical method. The vasoformative capability and genetic stability of EPCs were cultured in matrigel, and examined by karyotype analysis. The oncogenicity of EPCs was verified by the tumorigenesis test in athymic mouse and soft agar. RESULTS: EPCs were successfully derived from the UCB, and could be passaged to at least 42(nd) generation and had strong abilities of proliferation, acLDL intake and vasoformation, but there was not oncogenicity. They expressed endothelial cell-surface antigens and maintained normal karyotype. CONCLUSION: The EPCs with proliferative potential can be isolated from the UCB. They can be passaged in long-term cultures without oncogenicity, and can maintain normal karyotype. The EPCs can be served as a new type of cells in cell and gene therapy.

[Azoospermia factor microdeletion on Y chromosome in patients with idiopathic azoospermia or severe oligozoospermia].

OBJECTIVE: To investigate the correlation between male infertility and Y chromosome microdeletions of azoospermia factor (AZF) regions, and to establish a reliable genetic diagnosis in idiopathic infertile male patients with azoospermia or severe oligozoospermia. METHODS: Multiplex PCR amplification of 6 sequence-tagged sites in AZF regions of the Y chromosome was examined among 100 normal karyotype male patients with azoospermia or oligozoospermia. RESULTS: Four patients (4%) had Y chromosome microdeletions, the microdeletions of 3 patients were idiopathic azoospermic and those of the other 1 patient were secretory azoospermia. CONCLUSION: The PCR-based Y chromosome microdeletion screening is simple and effective in the diagnosis of patients with severe male infertility. Microdeletion of Y chromosome is one of the major causes of severe dyszooospermia.

[Preimplantation genetic diagnosis of Duchenne muscular dystrophy by single cell triplex PCR].

OBJECTIVE: To detect two exons of Duchenne muscular dystrophy (DMD) gene and a gender discrimination locus amelogenin gene by single cell triplex PCR, and to evaluate the possibility of this technique for preimplantation genetic diagnosis (PGD) in DMD family with DMD deletion mutation. METHODS: Single lymphocytes from a normal male, a normal female, two DMD patients (exon 8 and 47 deleted, respectively) and single blastomeres from the couples treated by the in vitro fertilization pre-embryo transfer (IVF-ET) and without family history of DMD were obtained. Exons 8 and 47 of DMD gene were amplified by a triplex PCR assay, the amelogenin gene on X and Y chromosomes were co-amplified to analyze the correlation between embryo gender and deletion status. RESULTS: In the normal single lymphocytes, the amplification rate of exons 8 and 47 of DMD and amelogenin gene were 93.8%, 93.8%, and 95.3% respectively. The false positive rate was 3.3%. In the exon 8 deleted DMD patient, the amplification rate of exon 47 of DMD and amelogenin gene was 95.8%, and the false positive rate was 3.3%. In the exon 47 deleted DMD patient, the amplification rate of exon 8 of DMD and amelogenin gene was 95.8%, and the false positive rate was 0. In the single blastomeres, the amplification rate of exons 8 and 47 of DMD and amelogenin gene was 82.5%, 80.0% and 77.5%, respectively, and the false positive rate was 0. CONCLUSION: The single cell triplex PCR protocol for the detection of DMD and amelogenin gene is highly sensitive, specific and reliable, and can be used for PGD in those DMD families with DMD deletion mutation.

[Identification of the origin of marker chromosome by comparative genomic hybridization].

OBJECTIVE: To identify the origin of the marker chromosome in a patient with chromosome aberration, and to provide the precise genetic diagnosis. METHODS: Comparative genomic hybridization (CGH) and fluorescence in situ hybridization (FISH) were performed to detect the known small marker chromosome in this patient. RESULTS: The small marker chromosome originated from chromosome 13 pter->q12. CONCLUSION: CGH and FISH can be used to detect the small marker chromosome, which is convenient and quick in detecting the origin of small marker chromosome.

[A mutation 1633-26(C-->A) in EXT1 gene causes multiple exostoses].

OBJECTIVE: To study the gene mutation in a patient with multiple exostoses, identify the disease-causing gene mutation. METHODS: Polymerase chain reaction and DNA sequencing were used to screen the EXT1 or EXT2 gene mutation, while mismatch primer amplification and restriction endonuclease digestion were performed to confirm the mutation. RESULTS: By DNA sequencing, a mutation in the seventh intron was detected and located at 26 bp of 3' splice site upstream in EXT1 gene, which was unreported before. Mismatch primer amplification and restriction fragment length polymorphism analysis suggested that this mutation was not detected in the normal control. CONCLUSION: The mutation 1633-26(C-->A) may be the disease-causing mutation in this patient with multiple exostoses.

[Identification and clone of human Alzheimer's disease related gene nicastrin promoter].

OBJECTIVE: To identify the promoter of human nicastrin (NCT) gene, a major component of gamma-secretase which is closely related with pathogenesis of Alzheimer's disease. METHODS: Promoter of human Alzheimer's disease related gene, nicastrin, a 1768 bp fragment was firstly isolated from human genomic DNA by PCR. This fragment's 3 flanking end was 4 bp upstream to the start codon ATG (+1) of the gene. This fragment was used as template, a series of deleted fragments were amplified and constructed to the pGL3-Enhancer plasmid with the artificial designed linkers. The relative activity of their promoter in Hela cells was studied by dual-luciferase assay. RESULTS: The 420 bp fragment showed the strongest activity, and the 237 bp fragment was the minimal fragment in length with activity. CONCLUSION: The promoter of NCT is located at -432/-133 region upstream the translational start codon, while its basal promoter is between -359/-90 that drives the transcription of reporter gene in Hela cells.

[Genetic linkage analysis in localizing a gene of autosomal dominant familial dilated cardiomyopathy with conduction defect].

OBJECTIVE: To localize the gene of autosomal dominant familial dilated cardiomyopathy with conduction defect. METHODS: A Chinese family which was diagnosed as dilated cardiomyopathy with conduction defect was studied. Venous blood (3 - 5 mL) from some family members was collected, and genomic DNA was extracted from the blood. Then whole genome wide scan was performed after excluding the known markers on the candidate loci (CMD1A, CMD1 E, CMD1F, and CMD1H) by two-point linkage analysis. RESULTS: No significant evidence for linkage was found in the two point linkage analyses to the known markers in the analyzed family. And the whole genome wide scan showed the maximum LOD score reached 2.68 at marker D3S1614 ( at recombination fraction theta = 0). CONCLUSION: The related gene in this kindred is located on 3q26 other than on CMD1A, CMD1H, CMD1E, and CMD1F.

A minidystrophin-EGFP fusion gene expressed in Cos-7 cells mediated by human source vector.

OBJECTIVE: To construct a human source vector containing minidystrophin-EGFP fusion gene and investigate its expression in Cos-7 cells. METHODS: The recombinant human source vector named pHrnDysG was constructed with PCR-clone methods. Three fragments of dystrophin gene were PCR amplified from normal human dystrophin gene cDNA (GenBank NM04006). These three fragments were ligated to generate a minidystrophin gene. The enhanced green fluorescent protein (EGFP) gene was fused to the C terminal of the minidystrophin gene, and then the pHrnDysG was finally obtained by cloning the fusion gene to pHrneo. Fluorescence microscope and RT-PCR were used to detect the expression of minidystrophin-EGFP fusion gene after the recombinant construct was transfected into Cos-7 cells by lipofectamine. RESULTS: Restrictive enzyme digestion analysis and sequencing confirmed that pHrnDysG vector was constructed successfully. After the recombinant pHrnDysG was transfected to Cos-7 cells, RT-PCR demonstrated that the fusion gene was successfully transcribed, and the green fluorescence was observed at the cell membrane. CONCLUSION: The minidystrophin-EGFP fusion gene mediated by pHrneo vector could express in Cos-7 cells and its products' localization in the cell membrane was the same as that of full length dystrophin. These results suggested that the recombinant human source vector pHrnDysG might be potentially used in studies on the gene therapy of Duchenne muscular dystrophy.

[Prenatal diagnosis of prelingual deafness by determination of SLC26A4 gene mutation].

OBJECTIVE: To identify deafness related gene and provide its prenatal diagnosis to avoid deaf fetus delivery. METHODS: DNA was extracted from amniotic cells in a pregnant woman close to 21 weeks' gestation, as well as from peripheral blood cells of the pregnant woman, her husband and their two sons. Screening for GJB2 and SLC26A4 gene mutations was firstly performed in the deafness proband (the first son of the couple), and then it was carried out in the fetus and the rest family members. RESULTS: The first child of the family, i.e., the proband, was homozygous in the IVS7-2A > G mutation of SLC26A4, the parents and the second child were carriers of the same mutation, while the fetus had a wild-type form. CONCLUSION: It is feasible to identify deafness related genes by screening for GJB2 and SLC26A4 mutation, thus providing correct prenatal diagnosis and avoiding deaf delivery of baby.

[Mutation analysis of PINK1 gene in Chinese patients with autosomal recessive early-onset parkinsonism type 6].

OBJECTIVE: To detect PINK1 gene mutations and study the clinical features in Chinese patients with autosomal recessive early-onset parkinsonism (AREP) type 6. METHODS: PINK1 gene mutations were detected using polymerase chain reaction (PCR), DNA sequence analysis, and restriction enzyme digestion analysis in 11 index probands of 11 AREP families. RESULTS: Two novel point mutations in PINK1 gene, C938T in exon four, leading to substitution of a threonine for methionine codon at amino acid 313 (T313M) and C1474T in exon seven introducing a stop codon at amino acid 492 (R492Stop), were found in two families. In another family, a synonymous mutation (Y454Y) was detected. The clinical features in patients with PINK1 mutations included early onset, slow disease progression, hyperreflexia, diurnal fluctuations with sleep benefit, and good response to levodopa. However, dyskinesias related to levodopa treatment were absent. CONCLUSION: PINK1 gene mutations are a common cause of AREP. PARK6 pedigrees have been firstly identified in Chinese Mainland. Clinical heterogeneity exists in PARK6.