Showing 4 results for Hek293
Volume 1, Issue 3 (10-2014)
Abstract
Background: Erythropoietin (EPO) is a glycoprotein hormone function to regulate the production of red blood cells. Deficiency of EPO is known to cause anemia in chronically infected renal patients and they require regular blood transfusion. Availability of recombinant EPO has eliminated the need for blood transfusion and now it is extensively used for the treatment of anemia. Glycosylation of erythropoietin is essential for its secretion, stability, protein conformation and biological activity. However, maintenance of human like glycosylation pattern during manufacturing of EPO is a major challenge in biotechnology. Currently, Chinese hamster ovary (CHO) cell line is used for the commercial production of erythropoietin but this cell line does not maintain glycosylation resembling human system. With the trend to eliminate non-human constituent from biopharmaceutical products, as a preliminary approach, we have investigated the potential of human emberyo kidney cell line (HEK293) to produce recombinant EPO. Methods: Initially, the secretory signal and Kozak sequences was added before the EPO mature protein sequence using overlap extension PCR technique. PCR-amplified cDNA fragments of EPO was inserted into mammalian expression vector under the control of the cytomegalovirus (CMV) promoter and transiently expressed in CHO and HEK293 cell lines. After RT-PCR analysis, ELISA and Western blotting was performed to verify the immunochemical properties of secreted EPO. Results: Addition of secretory signal and Kozak sequence facilitated the extra-cellular secretion and enhanced the expression of EPO protein. Significant expression (P < 0.05) of EPO was observed in the medium from HEK293 cell line. Conclusions: HEK293 cell line has a great potential to produce glycosylated EPO, suggesting the use of this cell line to produce glycoproteins of the therapeutic importance resembling to the natural human system.
M. Rasekhi , B. Bakhshande , M. Sadeghizadeh , A. Salimi , M. Soleimani ,
Volume 9, Issue 1 (1-2018)
Abstract
Aims: The induction of artificial over-expression of miRNAs is an appropriate approach to more effective cell differentiation. The significant role of microRNA-1(miR-1) has been reported in the development and differentiation of cardiac cells. Lentivirus is an effective vector for stable cell line production. The aim of this study was the production of recombinant HEK293T with miR-1 overexpression as a biological model for cardiac studies.
Materials & Methods: In this experimental study, HEK 293T cells were cultured in DMEM medium with 10% Fetal Bovine Serum (FBS) and L-glutamine 2mM and Penicillin-Streptomycin 1X in incubator medium. After cloning of miR-1 gene, recombinant clones were selected and the recombination was confirmed by sequencing. The miR-1 carrying vector and auxiliary vectors were packaged in the HEK293T to produce the recombinant virus. The infection of HEK293T by recombinant virus was performed in order to achieve stable cell line. Then, GFP fluorescent marker evaluated the efficiency of transfection and effective virus dilution. Finally, the alteration in expression level of miR-1 was assessed by qPCR. Data analysis was performed by comparing the threshold cycle and Pfaffl method.
Findings: The most GFP expression was detected in transfected cells by 150 micromole dilution. GFP fluorescent marker facilitated optimization and purification of recombinant cells. qPCR investigation demonstrated the significant increase in expression of miR-1 in transfected cells in comparison to controls.
Conclusion: The stable recombinant HEK293T miR-1 over-expressing cell line in lentivirus can be utilized as a suitable biological model for investigation of cardiac evolution and development processes.
S. Askari, S. Hasannia, R. Hasan Sajedi, V.r. Yassaee,
Volume 10, Issue 3 (9-2019)
Abstract
CEL I endonuclease pertaining to the S1 endonuclease family. The enzyme, with its high specificity, has the ability to identify different types of mutations and base replacement in the DNA molecule, which makes it important in commercial products to use in research and clinical laboratories. Although the enzyme exists in the celery plant, the extraction of the enzyme is a time-consuming process and not economical and the yield of the final product is low. In addition, due to its post-translational modifications to achieve the final active structure, no report has published to indicate the expression of the active form of this enzyme in the bacterial hosts yet. Therefore, one of the production sources of the active form of this enzyme is its cloning and expression in eukaryotic hosts, including yeast and mammalian cell lines. In this study, in order to express CEL I endonuclease, its gene sequence was optimized and synthesized in host eukaryotic HEK293T. CEL I was subcloned by double digest with KpnI and XhoI enzymes in the pBudCE4.1expression vector. The expression construct was transfected into the HEK293T cell line by lipofectamine transfection. Expression of the recombinant protein after transfection into HEK293T cells was confirmed by multiple methods including polyacrylamide gel electrophoresis, ELISA, RT-PCR, and western blot reaction. The analysis of SDS-PAGE and western blot data confirmed the molecular weight of approximately 30kDa. Purification was carried out with the Ni-NTA column and the amount of purified protein was determined to be about 0.2mg/ml. Finally, the activity of endonuclease enzyme was investigated on both normal and mutated heteroduplex DNA amplified by PCR. The results showed that the expression of this protein in HEK293T host had shown sufficient activity.
ّfahimeh Ghasemi, Alireza Zomorodipour, Ali Asghar Karkhane, Mohammadreza Khorramizadeh,
Volume 11, Issue 3 (10-2020)
Abstract
Hyper-glycosylation is an approach to introduce new N-glycosylation consensus sequence(s) (
َAsn-Xxx-Ser/Thr three-peptide) into a protein primary amino acid sequences by site-directed mutagenesis which is followed by the attachment of a new glycan to the Asn residue located within the three-peptide sequence. Hyper-glycosylation has attracted lots of interest especially in the protein therapeutics industry. The attached glycan may improve the pharmacokinetic properties of the hyper-glycosylated priteins and increase their half-life in the bloodstream. In the current study, a new N-glycosylation site was introduced into N-terminal Gla domain of hFIX. Arg
37 position of mature hFIX was targeted to be converted into Asn residue by site-directed mutagenesis using overlap extension PCR. Recombinant expression plasmids for native and mutant hFIX were constructed. The expression of the recombinant wild-type and mutant hFIX was analyzed in mammalian HEK293 cells using gradient SDS-PAGE and western blotting analysis. The results indicated in higher molecular weight for R37N mutant in compared with the native protein. The glycan attachment to R37N mutant was further confirmed by PNGase digestion and western blotting.
