Effect of RHAG variants identified in Chinese population on RHAG mRNA splicing in vitro / 中国输血杂志

【Objective】 To study the effect of RHAG variants identified in Chinese population on mRNA splicing by minigene splicing assay(MSA) in vitro. 【Methods】 The pSplicePOLR2G minigene expression plasmids were constructed for 10 RHAG mutations with relatively high distribution frequency in Chinese population near splicing sites or synonymous mutations by analyzing the RHAG gene data in the KMxD database. Then, the wild-type and mutant plasmids were transfected into HEK 293T cells, and RNA was extracted 48 hours after transfection. After reverse transcription, specific primers were used for PCR amplification, and then agarose gel electrophoresis and capillary electrophoresis were performed to determine whether the mutations will affect the normal splicing of exons. 【Results】 MSA in vitro showed that 2 mutations (c.158-5delT, c. 807+ 3A>C) near the splicing site reduced the amount of normal transcripts slightly. The remaining 8 synonymous mutations(c.312G>A, c. 341+ 3G>A, c. 609C>T, c. 681G>A, c. 861G>A, c. 957T>A, c. 984T>C and c. 1139-7G>A) had no impact on the splicing of RHAG mRNA. 【Conclusion】 This study showed that RHAG gene was conservative in terms of splicing, and the mutations near splicing sites and synonymous mutations were less likely to cause abnormal splicing of RHAG gene.

Novel mutation c.1210-3C > G in cis with a poly-T tract of 5T affects CFTR mRNA splicing in a Chinese patient with cystic fibrosis / 医学前沿

Cystic fibrosis (CF) is a rare autosomal recessive disease with only one pathogenic gene cystic fibrosis transmembrane conductance regulator (CFTR). To identify the potential pathogenic mutations in a Chinese patient with CF, we conducted Sanger sequencing on the genomic DNA of the patient and his parents and detected all 27 coding exons of CFTR and their flanking intronic regions. The patient is a compound heterozygote of c.2909G > A, p.Gly970Asp in exon 18 and c.1210-3C > G in cis with a poly-T of 5T (T5) sequence, 3 bp upstream in intron 9. The splicing effect of c.1210-3C > G was verified via minigene assay in vitro, indicating that wild-type plasmid containing c.1210-3C together with T7 sequence produced a normal transcript and partial exon 10-skipping-transcript, whereas mutant plasmid containing c.1210-3G in cis with T5 sequence caused almost all mRNA to skip exon 10. Overall, c.1210-3C > G, the newly identified pathogenic mutation in our patient, in combination with T5 sequence in cis, affects the CFTR gene splicing and produces nearly no normal transcript in vitro. Moreover, this patient carries a p.Gly970Asp mutation, thus confirming the high-frequency of this mutation in Chinese patients with CF.

Analysis of clinical phenotype and gene variants in a patient with classic tuberous sclerosis complex / 中华皮肤科杂志

Objective:To analyze clinical phenotypes and pathogenic mutations of a patient with classic tuberous sclerosis complex.Methods:Clinical data was collected from a patient with classic tuberous sclerosis complex. Next-generation sequencing was performed to screen pathogenic gene variants, and Sanger sequencing to verify the mutations. Minigene plasmids were constructed and transfected into the human renal epithelial cell line 293T, and RNA was extracted for transcriptional analysis.Results:The patient clinically presented with recurrent epileptic seizures, facial angiofibroma, periungual fibroma, pulmonary lymphangioleiomyomatosis, renal angiomyolipoma and multiple osteosclerosis. Next-generation sequencing revealed a suspected pathogenic variant in the TSC2 gene in the patient. Sanger sequencing identified a heterozygous mutation c.336_336+15delGGTAAGGCCCAGGGCG in exon 4 of the TSC2 gene in the patient, but not in his parents or 100 unrelated healthy controls. Moreover, this mutation had not been previously reported. The minigene experiment showed changed mRNA sequence of the TSC2 gene in this patient with loss of the authentic splice site in exon 4 and insertion of a 74-bp intron, which shifted the splice site 90 bp downstream (r.336delins336+16_336+90) .Conclusion:The novel heterozygous mutation c.336_336+15delGGTAAGGCCCAGGGCG in exon 4 of the TSC2 gene can lead to aberrant splicing, and may contribute to tuberous sclerosis complex in this patient.

A novel splice site mutation in OTC gene of a female with ornithine transcarbamylase deficiency and her asymptomatic mosaic father

Ornithine transcarbamylase deficiency is an X-linked disease with a wide range of clinical severity and manifestation age both in males and females. Here, we describe a case which is caused by a novel c.78-1G[A splice site mutation, which on mRNA level leads to a 1-bp deletion and a frameshift (c.78delG (p.C27Vfs*11)) in OTC exon 2 in a young girl. The same mutation has been detected in a mosaic state in her asymptomatic father.

Comprehensive genetic diagnosis of patients with Duchenne/Becker muscular dystrophy (DMD/BMD) and pathogenicity analysis of splice site variants in the DMD gene / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) are caused by mutations in the DMD gene. The aim of this study is to identify pathogenic DMD variants in probands and reduce the risk of recurrence of the disease in affected families. Variations in 100 unrelated DMD/BMD patients were detected by multiplex ligation-dependent probe amplification (MLPA) and next-generation sequencing (NGS). Pathogenic variants in DMD were successfully identified in all cases, and 11 of them were novel. The most common mutations were intragenic deletions (69%), with two hotspots located in the 5′ end (exons 2–19) and the central of the DMD gene (exons 45–55), while point mutations were observed in 22% patients. Further, c.1149+1G>A and c.1150-2A>G were confirmed by hybrid minigene splicing assay (HMSA). This two splice site mutations would lead to two aberrant DMD isoforms which give rise to severely truncated protein. Therefore, the clinical use of MLPA, NGS, and HMSA is an effective strategy to identify variants. Importantly, eight embryos were terminated pregnancies according to prenatal diagnosis and a healthy boy was successfully delivered by preimplantation genetic diagnosis (PGD). Early and accurate genetic diagnosis is essential for prenatal diagnosis/PGD to reduce the risk of recurrence of DMD in affected families.

A novel splicing mutation identified in a Chinese family with Alport syndrome and analysis of its pathogenicity / 医学研究生学报

Objective The purpose of this study was to identify a pathogenic variant in a Chinese family with Alport syndrome and analyze the pathogenicity of the variant. Methods Using targeted region capture and high-throughput sequencing technology, we identified the genetic variant of the proband with Alport syndrome, verified the variant in the family members by Sanger sequencing, and analyzed its influence on the pre-mRNA splicing process by in vitro minigene assay. Results A heterozygous variant c.2767G>T (p.Gly923Cys) was identified as a novel variant in exon 32 of the COL4A5 gene in the proband, which was confirmed by Sanger sequencing to be cosegregated with disease in the family. The minigene assay demonstrated that the c.2767G>T variant induced deletion of exon 32 of the COL4A5 gene. Conclusion A novel COL4A5 mutation was identified by targeted region capture and high-throughput sequencing, which has enriched the gene mutation spectrum of Alport syndrome. The exonic mutation c.2767G>T confirmed to be a splicing mutation by in vitro minigene assay, which may lead to a deeper insight into the molecular pathogenesis of Alport syndrome.

Intron mutations of argininosuccinate lyase (ASL) gene exist in a family with argininosuccinic aciduria / 临床检验杂志

Objective@#To perform gene detection and gene mutation analysis in a family with inherited metabolic diseases characterized as increased citrulline (Cit) by the MS/MS assay. @*Methods@#The peripheral blood samples were collected from the family members, and genomic DNA was extracted for gene diagnosis, which was performed by the whole exon sequencing method. The novel mutation gene was cloned into pcDNA3.1(+) vector, and its pathogenicity was verified by the Mini-gene assay in cultured cells in vitro. @*Results@#The clinical diagnosis of the proband as argininosuccinic aciduria (ASA) was clear. Two pathogenic mutations, c.281G＞T (p.Arg94Leu) and c.208-15 T＞A, were detected in the argininosuccinate lyase (ASL) gene, and they were not reported previously. The Mini-gene expression in vitro confirmed that c.208-15 T＞A could cause aberrant splicing, resulting in the retention of 13 bp in intron 2. @*Conclusion@#Two new pathogenic mutations of ASL gene, c.208-15 T＞A and c.281G＞T, are found in an ASA family, which enriches the mutation profile of ASL gene. The Mini-gene assay is a simple and effective tool for the research of intron mutations.

Study on antitumor effect of minigene DNA vaccine derived from Carcinoembry-onic Antigen ( CEA) gene in mice / 中国免疫学杂志

Objective:To observe the immunological activity of haploid vaccine and three tandem repeats of minigene DNA vac -cine derived from Carcinoembryonic Antigen (CEA) gene.Methods:The immunoreaction was induced by intramuscular injection with pc-DNA3.0,pcDNA-CEA625-667 and pcDNA-triCEA625-667 in BALB/c.Four weeks after injection,the spleen cells and serum were separa-ted respectively from the mice for the in vitro assessment .Changes of the T lymphocytes subset was analyzed by flow cytometry .Lymph proliferation responses were tested by 3 H-TdR incorporation ,IFN-γ,IL-4 and GM-CSF in their cultural supernatants were detected with ELISA and seral IgG antibody against CEA were detected with Western blot and ELISA .Results:The difference of the ratio of CD 4+/CD8+of the mice immuned by pc-DNA3.0,pcDNA-CEA625-667 or pcDNA-triCEA625-667 was not significant.Lymph proliferation responses were more significant in the mice immuned by pcDNA-CEA625-667 and pcDNA-triCEA625-667 in a shorter time by contrast with na ?ve mice.Low tilter IgG antibody against CEA was detected in the antiserum of the mice immuned by repeats of minigene DNA vaccine , which suggested the activation of helper T-cell.ELISA showed that the level of IFNγin the 3 days culture of the splenocytes was rela-tively higher in the groups of minigene DNA vaccination than in the control groups ,while IL-4 expression was absent in all groups .The immune response level elicited by three tandem repeats of minigene DNA vaccine pcDNA -triCEA625-667 was superior to that elicited by pcDNA-CEA625-667 ,which showed that any immunogenic inadequacies in minigene presentation can be rectified by linking itself in a string-of-beads vaccine.Conclusion:The haploid vaccine and three tandem repeats of minigene DNA vaccine derived from CEA geneboth can not change the ratio of CD 4+/CD8+but can induce the activation of helper T-cell and skew T -cells toward Th -1 response.The immune response level elicited by three tandem repeats of minigene DNA vaccine was superior to thatelicited by haploid vaccine .

Observation of anti tumor activity in vivo of three tandem repeats of minigene DNA vaccine derived from CEA gene / 中国免疫学杂志

Objective:To observe the inhibitory effect of haploid vaccine pcDNA-CEA625-667 and three tandem repeats of minigene DNA vaccine pcDNA-triCEA625-667 derived from CEA gene on tumor in mice bearing tumor and the changes of survival time. Methods:The experimental animal model of mouse liver cell carcinoma was established and the mice were immunized with pcDNA-CEA625-667 and three series of DNA vaccine. Some of the mice were treated with normal saline as control group. The growth curve of tumor growth curve was recorded and the effect of vaccine on the survival time of tumor bearing mice was observed. Results:Compared with the normal saline control group,the two vaccines were able to significantly inhibit the tumor size and growth rate ( P<0. 01 ) of CEA positive tumor bearing mice,the inhibition of pcDNA-triCEA625-667 vaccine group was significantly better than the pcDNA-CEA625-667 vaccine group (P<0. 01),while the two were not inhibited tumor growth in CEA negative tumor bearing mice. The average survival time of the pcDNA-CEA625-667 vaccine group was(48. 50±6. 73)d,and there was significant difference (P<0. 01) compared with the saline control group ( 39. 00 ± 6. 64 ) d. The survival time ( 48. 50 ± 6. 73 ) d of the pcDNA-triCEA625-667 vaccine group was significantly higher than that of the normal saline control group and the pcDNA-CEA625-667 vaccine group (P<0. 01). The survival time of CEA negative tumor bearing mice could not be prolonged in the two groups. Conclusion:Either the haploid or the three series of the DNA vaccine,were able to significantly inhibit tumor growth rate (P<0. 01) and significantly prolong the survival time (P<0. 01) of CEA positive tumor bearing mice,but they had no therapeutic effect on CEA negative tumor bearing mice.

Tumor specific immune response induced by three tandem repeats of CEA mini gene DNA vaccine and safety evaluation / 中国免疫学杂志

Objective:To observe the specific killing effect on tumor cells of the spleen cells in mice immunized with three tandem repeats of CEA minigene DNA vaccine pcDNA-triCEA625-667 and to evaluate the safety of the vaccine. Methods: The BALB/c mice were randomly divided into blank vector group ( pcDNA3. 0 ) , haploid vaccine group ( pcDNA-CEA625-667 ) and tandem repeats vaccine group (pcDNA-triCEA625-667). The mice received a total of 4 intramuscular immunization every 10 days once. The changes of body weight,survival state were recorded and the levels of serum ALT and serum creatinine were detected. The specific CTL killing activity of spleen cells in accinated mice on mouse hepatoma cells(H22-CEA+),gastric cancer cells(MFC-CEA+),colorectal cancer cells ( CT26-CEA+) with high expression of CEA and mouse hepatoma cells ( H22-CEA-) without expression of CEA was detected. Results:The two vaccines had strong killing activity on CEA positive liver cancer,gastric cancer and colon cancer cells,and the difference was statistically significant ( P<0. 01 ) compared with the PcDNA3. 0 group. And they had almost no effect on CEA negative tumor cells (H22-CEA-). The killing activity on liver cancer cell(H22-CEA+) and gastric cancer cell(MFC-CEA+) induced by pcDNA-triCEA625-667 was stronger than that induced by pcDNA-triCEA625-667(P<0. 05). The survival status,change of body weight and function of liver and kidney of the mice were not affected by the vaccine. Conclusion:There was no adverse reaction in the course of vaccine immunization. The minigene DNA vaccine derived from CEA can induce tumor specific CTL effect and the immune response level elicited by three tandem repeats of minigene DNA vaccine was superior to that elicited by haploid vaccine.

The Expression of SRp38 Gene in Mouse Retina and It's Regulation of Alternative Splicing of GluR-B Minigene / 生物化学与生物物理进展

SR proteins play important roles in regulating alternative pre-mRNA splicing. As a newly discovered neural and reproductive tissue specific SR protein, SRp38 regulates the alternative splicing of several genes important for neural function, such as GluR-B, Trk-C and NCAML1. It also acts as a splicing inhibitor during mitosis or stress response in order to prevent wrong splicing. The expression of SRp38 in mouse retina was investigated by Western blot and immunohistochemistry (IHC) analyses. The result shows that the expression of SRp38 proteins in mouse retina is region-specific, with extensive distribution in the outer and inner plexiform layers, inner nuclear layer and ganglion cell layer, but no expression in outer nuclear layer. Double staining of isolated retina cells with anti-SRp38 and anti-Trk-C antibodies showed that SRp38 is localized in the dendrites, somata and axon terminals of rod-bipolar cells. By transient co-transmission of over-expressed SRp38 plasmid and RT-PCR analyses, the further results showed that overexpressed SRp38 could promote the splicing of the Flip isoform of GluR-B minegene in R28 cells. The result suggests that SRp38 may play important roles in the retinal function, possibly via regulating the neural-specific alternative splicing of genes as GluR-B.