Resistance of Cloned 1F5 Chimeric Anti-CD20 Antibody Heavy-Chain Gene to DNA Polymerase due to a Predicted Hairpin Structure

Background: Formation of secondary structure such as DNA hairpins or loops may influence molecular genetics methods and PCR based approaches necessary for genetic engineering, in addition to gene regulation. Materials and Methods: A polymerase chain reaction with splice overlap extension (SOE-PCR) was used to create fully synthetic 1F5 chimeric anti-CD20 heavy- and light-chain genes. The chimeric genes were cloned into the pCR-Blunt II-TOPO vector following by cloning into the pBudCE4.1 expression vector. Prediction of secondary structure was performed with the Vienna RNAfold webserver. PCR and sequencing across the predicted secondary structure of chimeric 1F5 heavy-chain gene was performed with multiple protocols for standard and GC-rich templates. Results: In our attempt to design vectors aimed to generate mouse-human chimeric antibody against CD20 (1F5), we found that the coding sequence of 1F5 chimeric heavy-chain gene constructed by SOE-PCR was resistant to polymerase during both PCR and sequencing reactions. Furthermore, we were also unable to analysis some positive transformants by restriction enzyme digestion. Encountering such difficulties to identify the cloned anti-CD20 chimeric heavy-chain gene, we found that the chimeric heavy-chain sequence is highly GC-rich and predicted to form a stable secondary structure. Conclusion: In conclusion, for the first time, we reported several difficulties with production of therapeutic chimeric 1F5 anti-CD20 antibody due to a predicted hairpin cluster correlates with barriers to PCR, sequencing and possibly restriction analysis. Our findings provide a probable note for researchers experiencing technical difficulties with construction of chimeric anti-CD20 antibody 1F5 gene vectors and also with other genes and molecular biology techniques requiring PCR-based method or restriction enzyme analysis.&nbsp

Impact of DNA methylation of the human mesoderm-specific transcript (MEST) on male infertility

Male infertility accounts for nearly 40%–50% of all infertile cases. One of the most prevalent disorders detected in infertile men is errors in the MEST differentially methylated region (DMR), which has been correlated with poor sperm indexes. The aim of our study was to characterize the methylation pattern of the MEST gene, along with assessing seminal factors and chromatin condensation in sperm samples from both infertile patients and fertile cases, all of whom were candidates for intracytoplasmic sperm injection. We collected forty-five semen specimens from men undergoing routine spermiogram analysis at the Infertility Treatment Center. The specimens consisted of 15 samples of normospermia as the control group, 15 individuals of asthenospermia, and 15 individuals of oligoasthenoteratospermia as the cases group. Standard semen analysis and the chromatin quality and sperm maturity tests using aniline blue staining were performed. The DNA from spermatozoa was extracted and treated with a sodium bisulfite–based procedure. The methylation measure was done quantitatively at the DMRs of the MEST gene by quantitative methylation-specific polymerase chain reaction (qMSP). The mean percentages of total motility, progression, and morphology in normospermia were significantly higher than oligoasthenoteratospermia and asthenospermia, and they were substantially higher in asthenospermia compared to oligoasthenoteratospermia (P ≤ 0.05). The mean percentages of histone transition abnormality and MEST methylation in oligoasthenoteratospermia were significantly higher than asthenospermia and normospermia (P ≤ 0.05). A negative correlation existed between the histone transition abnormality and MEST methylation with sperm parameters. In conclusion, chromatin integrity, sperm maturity, and MEST methylation may be considered important predictors for addressing male factor infertility. Therefore, we suggest that male infertility may be linked to methylation of the imprinted genes

Optimization of plasmid electrotransformation into Escherichia coli using Taguchi statistical method

Electroporation is a mechanical method used to introduce polar molecules into a host cell through the cell membrane. In this procedure, a large electric pulse temporarily disturbs the phospholipid bilayer allowing molecules like DNA to pass into the cell. Application of statistical methods to determine the appropriate processes have been suggested for genetic engineering and biotechnology technique such as electroporation. This study explains the use of Taguchi statistical method to optimize the conditions for efficient plasmid transformation into Escherichia coli via electroporation. In order to improve electroporation, optical density of bacteria, recovery time and electrical parameter (field strength and capacitance) were optimized using the Taguchi statistical method. ANOVA of obtained data indicated that the optimal conditions of electrotransformation of pET-28a (+) plasmid into Escherichia coli BL21(DE3)pLysS was 0.7, 120 min, 12 kV/cm and 50 μF, for optical density of cell culture,  recovery time, field strength and capacitance, respectively. The most significant alterations are decrease in field strength and increase in optical density in comparison with common electroporation protocol. The maximum level of plasmid transformation obtained under optimal condition was 8.7×108 transformants/μg DNA plasmid, which was 6.7 fold higher than the control condition.Keywords: Electroporation, Taguchi statistical method, Plasmi

Evaluation of the association between TNF-α-1031 T/C polymorphism with oral lichen planus disease

Abstract Background Oral lichen planus (OLP) is a T-cell-mediated autoimmune disease that affects the epithelial cells of the oral cavity. This study was performed to investigate any possible relationship between − 1031(T/C) polymorphism (rs1799964) of the tumor necrosis factor α (TNF-α) gene with the risk and severity of oral lichen planus (OLP) disease among an Iranian population. Method Saliva samples were collected from 100 patients with OLP and a similar number of healthy controls (age and sex-matched). Then, DNA was extracted from the collected samples for genotyping TNF-α-1031 T/C polymorphism using the PCR-CTPP method. The results were assessed using SPSS software. Results The findings revealed a significantly higher prevalence of the C allele in OLP patients (53%) compared to healthy controls (36%), suggesting an association between TNF-alpha gene polymorphism and OLP. A multivariate logistic regression analysis supported this finding, as the presence of the C allele was significantly associated with an increased risk of OLP [χ2 = 4.17, p = 0.04, 95% CI = 1.01–2.65, OR = 1.64]. However, our data indicated no significant association between TNF-alpha-1031 T/C gene polymorphism and OLP severity. Conclusions These findings provide the first evidence supporting a possible role of TNF-α-1031 T/C gene polymorphism in OLP susceptibility in the Iranian population. The findings of this study demonstrate a positive association between TNF-α-1031 C/T allele distribution and the risk of OLP disease in the Iranian population. Therefore, carrying the C allele may increase the susceptibility to OLP disease

Association of interleukin-8 polymorphism (+ 781 C/T) with the risk of oral Lichen Planus disease

Abstract Background Oral Lichen Planus (OLP) is a chronic inflammatory mucosal disease. The pathogenesis of OLP is unknown. The Single Nucleotide Polymorphism (SNP) that occurs in the regulatory position + 781 could affect the expression of interleukin-8. This polymorphism is probably associated with increased serum levels of IL-8. The current study aimed to investigate the genotype and allele frequencies of IL-8( + 781 C/T) in OLP patients and whether it is associated with the severity of OLP disease in an Iranian population. Methods Three milliliters of saliva were taken from 100 patients with OLP and 100 healthy individuals who were matched in age and gender. After DNA extraction from saliva samples of patients and healthy individuals, the genotype of IL-8 at position + 781 is detected using the PCR-RFLP method. The results were analyzed using SPSS software. Results Frequency of C/C, T/C, and T/T genotypes at position IL-8 + 781 gene in the patient group were 47%, 41%, and 12%, respectively, and in the control group, were 37%, 42%, and 21%. The difference between the two groups regarding allele frequency distribution was statistically significant (χ2 = 3.86, p = 0.049, 95% CI = 0.44-1, OR = 0.66). Our results indicated the significantly higher frequency of the TT genotype in the erosive OLP compared to the nonerosive group (p = 0.03, OR = 0.89, 95% CI = 0.49–1.6). Conclusion This study depicted the difference in the frequency of SNP IL-8 + 781 C/T allele in the patient and control groups had a significant association with the risk of OLP. In addition, our data revealed that IL-8 + 781 C/T polymorphisms might be associated with the severity of OLP in the Iranian population

Primary culture of human skin melanocyte and comparison of culture in the presence and absence of phorbol ester

Background: Primary culture takes place following the cell isolation from tissues. Isolation and culture of melanocytes based on their roll in the protection of body against hazardous sun rays, production of skin, cornea and hair color is really important. This study was done to set isolation, culture and proliferation of melanocytes from children foreskin and adult eyelashes, and also comparison of two types of melanocyte culture medium. Methods: Human foreskin and eyelash samples were used for melanocyte isolation and culture. After isolation of epidermis from dermis, epidermis cell suspensions were prepared by enzymatic digestion. The isolated cells were cultured in two melanocyte selective culture media. Immunocytochemistary and reverse transcription-polymerase chain reaction (RT-PCR) assays were used for confirmation of isolated and cultured melanocytes. Results: Our results indicated that isolated melanocyte cultured in the selective medium without phorbol esters is better than the melanocytes cultured in selective medium cont-aining phorbol esters not only morphologically but also physiologically and from the aspect of cell adhesion. In addition, the results showed that isolated melanocyte from adult eyelashes are more dendritic than melanocytes isolated from children foreskin. Conversely, our results indicated that the number of cell passages in melanocyte isolat-ed from foreskin is more than melanocytes isolated from adult eyelashes. Conclusion: Melanocytes cultured in selective medium containing convenient growth factors in absence of phorbol esters show more native physiological and adhesive properties. In addition, melanocyte isolated from younger tissues such as foreskin have better proliferative and sub-culturing properties so we suggest isolation and culture of younger tissues

The study of <i>HMOX1 </i>DNA methylation and gene expression and the diagnostic potential of <i>miR-153-3p</i> in preeclampsia

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