Objective To detect the disease-causing mutations in Duchenne muscular dystrophy (DMD) gene of DMD or Becher's muscular dystrophy (BMD) patients or carriers. Methods Multiplex ligation-dependent probe amplification (MLPA) and denaturing high performance liquid chromatography (DHPLC) were coupled to analyze the disease-causing mutations in DMD gene. Results Ten patients were detected to have deletions in different exons; 1 patient was caused by duplication of exon 50 using DHPLC analysis, and 4 patients were found to be caused by non-sense point mutations. However, the disease-causing mutations of other 5 patients remained to be determined. Conclusion MLPA coupled with DHPLC analysis can be used to detect the disease-causing mutations of DMD or BMD systematically, and provide valuable information for the affected families in preventing from recurrence of DMD or BMD.

OBJECTIVETo compare the effectiveness of using multiple ligation probe amplification (MLPA) and denaturing high-performance liquid chromatography (DHPLC) in screening the exon deletions and duplications of the DMD gene.

METHODSMLPA technique was applied to detect exon deletions and duplications previously confirmed by denaturing high-performance liquid chromatography (DHPLC).

RESULTSFrom October 2004 to October 2005, 22 unrelated DMD probands and their possible female relatives with clinical diagnosis with dystrophinopathy at our hospital entered this study. Both DHPLC and MPLA detected DMD gene depletion in 11 probands and DMD duplications in 3 probands. MLPA detected deletions and duplications in 2 probands, which were not detected by DHPLC. MLPA also successfully identified the carriage status of the potential female carriers of the probands.

CONCLUSIONCompared with DHPLC and traditional PCR techniques, MLPA is a superior tool to analyze the deletions and duplications in affected males as well as in the identification of the carriage status of potential females carriers.

Chromatography, High Pressure Liquid ; Female ; Gene Deletion ; Gene Duplication ; Genetic Predisposition to Disease ; Humans ; Male ; Muscular Dystrophy, Duchenne ; genetics ; Mutation ; Nucleic Acid Amplification Techniques ; methods

OBJECTIVETo detect genomic deletion and duplication mutations in the dystrophin gene of the Duchenne muscular dystrophy (DMD) patients and their potential female carriers.

METHODSGenomic deletions and duplications of the DMD gene in 32 affected males and 27 potential female carriers were screened by mutiplex ligation-dependent probe amplification (MLPA).

RESULTSOf the 32 investigated affected males, 24 were detected to have deletions of one or more exons of the DMD gene, 1 patient had a duplication from exon 5 to 55, 1 patient had a nonsense point mutation (R768X) in exon 19, the other 6 affected males were predicted to have possible disease-causing point mutations. MLPA analysis showed a DMD deletion or duplication in 18 female relatives, and the female carriers had the same deletion or duplication as their probands, respectively.

CONCLUSIONMLPA analysis is proven to be an efficient tool for identification of both affected males and female carriers of DMD rearrangements in cases in which the disease-causing mutation in the affected male was not known. It could provide useful information for the genetic counseling of the family involved.

Codon, Nonsense ; DNA Mutational Analysis ; methods ; Dystrophin ; genetics ; Female ; Gene Duplication ; Genetic Predisposition to Disease ; genetics ; Genotype ; Heterozygote ; Humans ; Male ; Muscular Dystrophy, Duchenne ; genetics ; Point Mutation ; Sequence Deletion

OBJECTIVETo detect the disease-causing point mutations in the dystrophin gene of Duchenne muscular dystrophy (DMD) patients.

METHODSThe approach of denaturing high performance liquid chromatography (DHPLC) coupling with sequencing was used to screen the point mutations of 79 exons and the untranslated regions of dystrophin gene without large deletions/duplications, which was in 6 unrelated DMD probands from 6 DMD families.

RESULTSFive disease-causing mutations, 697-698insGT, C616T, G1255T, C4279T, and C2302T, were ides created the new stop codons in downstream sites of mutations, respectively. In addition to the disease-causing point mutations, a point mutation T5586+61A in intron 39 was also found at patient 3, and a missense mutation A694T in exon 8 was detected at patient 5. Four point mutations, C2168+13T, 5740-13dupG, G5234A and C5280T, were also detected at patient 6 whose causative point mutation was unavailable. Seven point mutations have not been reported previously. Bi-directional PCR amplification of specific alleles (Bi-PASA) method was established to distinguish the haplotypes of heterozygote or homozygote in a single PCR reaction.

CONCLUSIONVia automated DHPLC screening or detecting the subexonic mutations in dystrophin gene is feasible to clinical laboratories, and also is a superior method in terms of sensitivity and efficiency.

Base Sequence ; Chromatography, High Pressure Liquid ; DNA Mutational Analysis ; Dystrophin ; genetics ; Gene Duplication ; Humans ; Male ; Muscular Dystrophy, Duchenne ; genetics ; Point Mutation ; Polymerase Chain Reaction ; Sequence Deletion

This study was purposed to explore the relationship between asparagine synthetase (AsnS) mRNA expression level and the sensitivity of leukemic cell lines to L-asparaginase. The AsnS mRNA expression level in 8 cell lines (Jurkat, HL-60, U937, NB4, THP-1, Namalwa, Karpas299 and K562) was determined by real-time quantitative PCR (RQ-PCR) based on fluorescence dye Eva Green before and after treatment with L-Asp, and the cell proliferation rates were analyzed by CCK-8 assay. The results showed that there was a significant disparity of AsnS expression level in 8 cell lines, and there were significant increases of AsnS expression level in cells co-cultured with L-Asp (p < 0.05). Of all these eight cell lines, cells sensitive to L-asparaginase had lower AsnS expression level and cells resistant to L-asparaginase had higher AsnS expression. U937 which was the most sensitive to L-asparaginase had the lowest AsnS expression level, while K562 was natural resistant to L-asparaginase and possessed of the highest AsnS level. It is concluded that the AsnS plays a critical role in regulating cellular biological behavior after depletion of asparagine, the AsnS mRNA expression level in cells reflects the sensitivity of cells to L-Asp. The results may imply the possibility for the use of L-asparaginase in leukemia with lower AsnS expression level.
Asparaginase ; metabolism ; pharmacology ; Aspartate-Ammonia Ligase ; metabolism ; Cell Line, Tumor ; Humans ; Leukemia ; enzymology

BACKGROUNDMultidrug resistance to chemotherapeutic agents is an important clinical problem during the treatment of leukemia. The resistance process is multifactorial. To realize the total factors involved in multidrug resistance, we analyzed the differentially expressed proteins of K562 and K562/ADM cells and we investigated one of the up-regulated proteins (CRKL) using siRNA to determine its role in K562/ADM cells.

METHODSAltered protein expressions between K562/S (K562 ADM-sensitive cell line) and K562/ADM (K562 multidrug resistant cell line induced by adriamycin) were identified by 2D-DIGE coupled with mass spectrometry. Meanwhile, we confirmed the differential expression of CRKL and Stathmin in both K562 and K562/ADM cells by Western blot analysis. Furthermore, we used RNA interference to silence the CRKL gene expression.

RESULTSAmong the 9 differentially expressed proteins, 3 were up-regulated in K562/ADM cells, while 6 were down-regulated in the K562/ADM cells compared with its parent cell line. The expression of CRKL was up-regulated significantly in K562/ADM cells, and it can be decreased by recombinant lentivirus. Moreover, the multidrug resistance of K562/ADM cells was efficiently reversed by silence of CRKL gene expression.

CONCLUSIONSThe data provided the differentially expressed proteins in K562 and its resistant cell line and highlights the power of 2D-DIGE for the discovery of resistance markers in cancer. We found CRKL may be a new protein involved in the multidrug resistance of leukaemia cells.

Adaptor Proteins, Signal Transducing ; analysis ; antagonists & inhibitors ; genetics ; Amino Acid Sequence ; Doxorubicin ; pharmacology ; Drug Resistance, Multiple ; Humans ; K562 Cells ; chemistry ; drug effects ; Molecular Sequence Data ; Neoplasm Proteins ; analysis ; Nuclear Proteins ; analysis ; antagonists & inhibitors ; genetics ; Proteomics ; Stathmin ; analysis

OBJECTIVETo construct the eukaryotic expression vector of human microdystrophin gene and observe its expression in rat mesenchymal stem cells (rMSCs) in vitro.

METHODSThe plasmid PBSK-MICRO containing human microdystrophin cDNA was digested by restriction endonuclease, and the resultant microdystrophin fragment was inserted into the NotI site of pcDNA3.1(+) to prepare the eukaryotic expression vector-pcDNA3.1(+)/ microdystrophin, which was identified by endonuclease digestion and sequencing. The recombinant plasmid was transfected into rMSCs via lipofectamine, and after G418 selection, the expression of microdystrophin was detected by RT-PCR and indirect immunofluorescence assay.

RESULTSMicrodystrophin gene fragment was correctly inserted into the plasmid pcDNA3.1(+), as conformed by sequencing and digestion with Not I and Hind III. The total mRNA of the transfected rMSCs was extracted and microdystrophin mRNA expression was found in the cells by RT-PCR. Indirect immunofluorescence assay for the protein expression of microdystrophin showed bright red fluorescence in the transfected rMSCs.

CONCLUSIONEukaryotic expression plasmid pcDNA3.1(+)/microdystrophin has been constructed successfully and microdystrophin can be expressed in transfected rMSCs in vitro, which may facilitate further research of Duchenne muscular dystrophy treatment by genetically modified allogeneic stem cell transplantation.

Animals ; Base Sequence ; Cells, Cultured ; Dystrophin ; biosynthesis ; genetics ; Fluorescent Antibody Technique, Indirect ; Gene Expression ; Humans ; Mesenchymal Stromal Cells ; cytology ; metabolism ; Molecular Sequence Data ; Peptide Fragments ; biosynthesis ; genetics ; Plasmids ; genetics ; RNA, Messenger ; biosynthesis ; genetics ; metabolism ; Rats ; Rats, Sprague-Dawley ; Reverse Transcriptase Polymerase Chain Reaction ; Transfection

OBJECTIVETo investigate the clinical and lab features of sibling brother and sister both with Duchenne muscular dystrophy (DMD).

METHODSWe conducted comprehensive clinical and lab investigations including the test of serum enzymes, electromyography (EMG), electrocardiography, color Doppler echocardiography, HE staining of skeletal muscles, immunohistochemical study of dystrophin and utrophin, multiple ligation probe amplification (MLPA) on exon 1-79 of dystrophin gene, and short tandem repeat-poly- merase chain reaction of CA repeats located in dystrophin gene.

RESULTSThese two patients were confirmed to suffer from DMD. They were characterized by typical features of DMD including typical clinical manifestations, increased serum enzymes, EMG presenting myogenic impairment, HE staining presentation belonging to DMD, negative dystrophin in brother, and inconstantly positive on the sarcolemma of sister. Furthermore, no deletion or duplication was found in the 1-79 exons of dystrophin gene. The suffering brother and sister carried the same maternal X chromosome.

CONCLUSIONSCarriers of DMD gene show typical clinical and laboratory manifestations of DMD. Comprehensive examinations should be performed for such carriers.

Dystrophin ; genetics ; Female ; Genetic Linkage ; Heterozygote ; Humans ; Male ; Muscular Dystrophy, Duchenne ; genetics ; metabolism ; physiopathology ; Siblings