Analysis of a patient with early-onset retinitis pigmentosa due to novel variants of CRB1 gene / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for a patient with early-onset retinitis pigmentosa (RP).@*METHODS@#A patient who had presented at the West China Hospital of Sichuan University on March 10, 2020 was selected as the study subject. The patient and his parents were subjected to whole exome sequencing (WES). Candidate variants were verified by Sanger sequencing and in silico analysis.@*RESULTS@#The patient has featured substantial loss of binocular vision field. Funduscopy revealed characteristic bone spicule-type pigment deposits, as well as attenuated retinal arterioles and pale-appearing optic discs. WES revealed that he has harbored compound missense variants of a RP-associated CRB1 gene, including c.2969T>C (p.Leu990Ser) and c.1816T>C (p.Cys606Arg), which were respectively inherited from his father and mother. Homozygous c.1816T>C (p.Cys606Arg) variant has been identified among RP patients, whilst the c.2969T>C (p.Leu990Ser) variant was unreported previously. Both variants were predicted as likely pathogenic based on the guidelines from the American College of Medical Genetics and Genomics (ACMG).@*CONCLUSION@#The novel compound heterozygous variants of the CRB1 gene probably underlay the early-onset RP in this patient. Above finding has enriched the mutational spectrum of the CRB1 gene.

A novel splicing acceptor variant of the FBN2 gene contributes to a case of congenital contractural arachnodactyly / 中华医学遗传学杂志

OBJECTIVE@#To identify the pathogenic variants from a patient with suspected congenital contractural arachnodactyly, and to explore the possible molecular genetic pathogenesis, so as to provide evidence for clinical diagnosis.@*METHODS@#Whole exome sequencing was performed for the patient. The splicing site variation of candidate pathogenic genes was verified by Sanger sequencing, and the new transcript sequence was determined by RT-PCR and TA-cloning sequencing.@*RESULTS@#The patient carried a heterozygous c.533-1G>C variant of FBN2 gene, which was not reported. The sequencing of mRNA showed that the variant leaded to the disappearance of the canonical splice acceptor site of FBN2 gene and the activation of a cryptic splice acceptor site at c.533-71, resulting in the insertion of 70 bp sequence in the new transcript. It was speculated that the polypeptide encoded by the new transcript changed from valine (Val) to serine (Ser) at amino acid 179, and prematurely terminated after 26 aminoacids. According to the guidelines of American College of Medical Genetics and Genomics, the variant of FBN2 gene c. 533-1G>C was determined as pathogenic (PVS1+PM2+PP3 ).@*CONCLUSION@#A novel splicing variant of FBN2 gene (c.533-1G>C) was identified, which can lead to congenital contractural arachnodactyly.

Genetic analysis of two couples with a history of multiple fetal malformations / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for a couple with recurrent conceptions of fetus with abnormal longbones, and another couple with a history of omphalocele.@*METHODS@#Genomic DNA was extracted from the peripheral blood samples from both couples. All exons and flanking regions were analyzed with next generation sequencing. Candidate variants were verified by Sanger sequencing.@*RESULTS@#Couple one was found to be heterozygous for, a c.997+1G>T splice-site variant and a missence c.871G>A(p.Glu291Lys) variant of the ALPL gene. Both variants were predicted to be pathogenic and may result in reduced function or loss of alkaline phosphatase. For couple two, the wife was found to harbor a novel c.637_652 delins CCC variant of the CDKN1C gene. This deletion-insertion variant resulted in frame-shift and loss of function (p.Ala213Profs*55) of the CDKN1C protein. Maternally inherited CDKN1C LOF variant has been found to underlie Beckwith-Wiedemann syndrome (BWS), which may manifest as omphalocele.@*CONCLUSION@#Dispite the lack the direct proof from the lost fetuses, the variants of ALPL and CDKN1C genes can explain the recurrence of fetal malformations for both couples.

Genetic analysis of a recurrent abnormal pregnancy case caused by a cryptic reciprocal autosomal translocation / 中华医学遗传学杂志

OBJECTIVE@#To provide genetic counseling for a couple with recurrent detection of fetal structural abnormality during second trimester pregnancy.@*METHODS@#The fetal tissue and peripheral blood samples of the couple were subjected to G banded chromosomal analysis, copy number variation sequencing (CNV-seq) and fluorescence in situ hybridization (FISH) assays.@*RESULTS@#CNV-seq has detected a 6.59 Mb duplication at 7p22.3-p22.1 and a 3.81 Mb deletion at 4p16.3 in the fetal tissue, though conventional karyotyping results of both parents were normal. FISH has confirmed that the father has harbored a cryptic translocation of t(4;7)(7p+,4q+,4p+,7q+).@*CONCLUSION@#The ultrasonographic abnormality of the fetuses may be attributed to the 7p microduplication and 4p microdeletion derived from the cryptic translocation carried by the father. Reciprocal translocation of tiny chromosomal segments should be suspected for couples with recurrent adverse pregnancies but apparently normal karyotypes.

Identification of proteins interacting with the circadian clock protein PER1 in tumors using bacterial two-hybrid system technique / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To identify protein-protein interaction partners of PER1 (period circadian protein homolog 1), key component of the molecular oscillation system of the circadian rhythm in tumors using bacterial two-hybrid system technique.</p><p><b>METHODS</b>Human cervical carcinoma cell Hela library was adopted. Recombinant bait plasmid pBT-PER1 and pTRG cDNA plasmid library were cotransformed into the two-hybrid system reporter strain cultured in a special selective medium. Target clones were screened. After isolating the positive clones, the target clones were sequenced and analyzed.</p><p><b>RESULTS</b>Fourteen protein coding genes were identified, 4 of which were found to contain whole coding regions of genes, which included optic atrophy 3 protein (OPA3) associated with mitochondrial dynamics and homo sapiens cutA divalent cation tolerance homolog of E. coli (CUTA) associated with copper metabolism. There were also cellular events related proteins and proteins which are involved in biochemical reaction and signal transduction-related proteins.</p><p><b>CONCLUSION</b>Identification of potential interacting proteins with PER1 in tumors may provide us new insights into the functions of the circadian clock protein PER1 during tumorigenesis.</p>

Image processing applying in analysis of motion features of cultured cardiac myocyte in rat / 生物医学工程学杂志

Study of mechanism of medicine actions, by quantitative analysis of cultured cardiac myocyte, is one of the cutting edge researches in myocyte dynamics and molecular biology. The characteristics of cardiac myocyte auto-beating without external stimulation make the research sense. Research of the morphology and cardiac myocyte motion using image analysis can reveal the fundamental mechanism of medical actions, increase the accuracy of medicine filtering, and design the optimal formula of medicine for best medical treatments. A system of hardware and software has been built with complete sets of functions including living cardiac myocyte image acquisition, image processing, motion image analysis, and image recognition. In this paper, theories and approaches are introduced for analysis of living cardiac myocyte motion images and implementing quantitative analysis of cardiac myocyte features. A motion estimation algorithm is used for motion vector detection of particular points and amplitude and frequency detection of a cardiac myocyte. Beatings of cardiac myocytes are sometimes very small. In such case, it is difficult to detect the motion vectors from the particular points in a time sequence of images. For this reason, an image correlation theory is employed to detect the beating frequencies. Active contour algorithm in terms of energy function is proposed to approximate the boundary and detect the changes of edge of myocyte.

The A-204C Polymorphism in CYP7A1 Gene Affects Its Promoter Activity / 中国生物化学与分子生物学报

cholesterol 7α-hydroxylase gene ( CYP7A 1 ) plays a key role in the catabolism of cholesterol into bile acids. To investigate whether the A-204C polymorphism in CYP7A1 gene affects the gene expression,using luciferase as the reporter gene, four recombinants were constructed by inserting forward or reverse sequence with A or C allele at the polymorphism site into the promoter-less vector pGL3-basic. The constructs were then transfected into four cell lines and the luciferase activity of each expression vector was examined by dual luciferase reporter gene assay system. The results showed that activities of the forward sequence of both genotypes were higher than that of reverse sequence. Promoter activity of the recombinants with A allele was about one third lower than that with C allele. According to the analysis with TRANSFAC database, there may exist a Zic3 binding site when there is the C allele at -204. Our study indicates that the A-204 C polymorphism in CYP7A1 promoter region decreases its promoter activity and thus represses the gene expression, possibly due to the lack of a potential Zic3 binding site.

Effect of isorhmnetin on circadian rhythms of DNA synthesis and expression of c-myc gene in Eca-109 cells of human oesophageal cancer / 生物医学工程学杂志

This study was focused on the circadian rhythms of DNA synthesis and the expression of c-myc gene in untreated and treated Eca-109 cells in human oesophageal cancer with isorhmnetin. The circadian rhythms of 3H-TdR incorporation and expression of c-myc gene in untreated and treated Eca-109 cells were measured by 3H-thymidine uptake assay and flow cytometry. The data collected were analyzed by ANOVA and Cosinor method. DNA synthesis and expression of c-myc gene in untreated group varied according to circadian time with statistical significance, the distribution curves of both DNA synthesis and the expression level of c-myc were fit for cosinor changes. The circadian rhythms of DNA synthesis and circadian parameters of c-myc expression in treated Eca-109 cells changed. The circadian parameters of DNA synthesis and expression level of c-myc varied after treatment by isorhmnetin. The effects of isorhmnetin on cell proliferation and c-myc expression reached the highest level from 20: 00 to 0: 00. The results provide a guidance for instituting the chemotherapy and chronotherapy of human tumors, when isorhmnetin is for use as anti-cancer agent.

Isolation, cultivation and identification of neural stem cell from human embryonic CNS / 生物医学工程学杂志

This is a study on the cultivation condition in vitro and differentiation of neural stem cells from human embryonic brain in order to find a way to get purified multipotential neural stem cells. The single cells was derived from the three-month embryonic brain digested with trypsin, some cells was frozen, the other cells were expanded with EGF and bFGF, the single-cell-clone was obtained by the way of limited dilution, and the serum was used to induce the cells differentiation. The cells were detected with the method of immunohistochemistry. The results showed that a lot of neurospheres could be seen in the presence of mitogens (both EGF and bFGF) and serum could induce neural stem cells to differentiate into neurons, astrocytes, and oligodendrocytes. These indicate that the survival and proliferation of neural stem cells rely on the cooperation of EGF and bFGF. The neural stem cells can also be harvested from the frozen cells.