An improved fixation method for chromosome preparation of Chinese hamster, Chinese hamster-human hybrid, and mouse cell lines

1986 ◽  
Vol 41 (3) ◽  
pp. 181-184 ◽  
Author(s):  
G. Korthof
Keyword(s):  
Cell Lines ◽  
Chinese Hamster ◽  
Mouse Cell ◽  
Chromosome Preparation ◽  
Fixation Method

scholarly journals DISTINCTIVE CHARACTERISTICS OF NUCLEOLI OF TWO ESTABLISHED CELL LINES

1971 ◽  
Vol 49 (3) ◽  
pp. 803-815 ◽  
Author(s):  
David M. Phillips ◽  
Stephanie G. Phillips
Keyword(s):  
Cell Lines ◽  
Cultured Cells ◽  
Chinese Hamster ◽  
Mouse Cell ◽  
Particulate Material ◽  
Gradual Disappearance ◽  
Established Cell ◽  
Nucleolar Volume ◽  
Light Area ◽  
Nucleolar Components

Nucleoli of cultured cells of the established lines KB and L were found to possess a distinctive fine structural organization. The major portion of the nucleolar volume was composed of compact, particulate material. Spheroidal fibrillar zones about 0.4 µ in diameter occurred within the particulate mass. These fibrillar zones had a central light area and a denser rim. Toyocamycin treatment, which sharply inhibited the appearance of newly synthesized RNA in the cytoplasm, caused the gradual disappearance of the fibrillar material from nucleoli. Actinomycin D treatment, which inhibited virtually all RNA synthesis, caused varying types of segregation of nucleolar components. The morphology of nucleoli of KB and L cells and the reorganization of these nucleoli in response to drugs appear to be different from those of nucleoli of freshly initiated Chinese hamster and mouse cell lines.

scholarly journals Differential activation of the hprt gene on the inactive X chromosome in primary and transformed Chinese hamster cells.

1989 ◽  
Vol 9 (4) ◽  
pp. 1635-1641 ◽  
Author(s):  
S G Grant ◽  
R G Worton
Keyword(s):  
Cell Lines ◽  
X Chromosome ◽  
Gene Activation ◽  
Chinese Hamster ◽  
Fibroblast Cell ◽  
Dna Demethylation ◽  
Hprt Gene ◽  
Primary Fibroblast ◽  
Chinese Hamster Cells ◽  
Inactive X Chromosome

We have investigated the genetic activation of the hprt (hypoxanthine-guanine phosphoribosyltransferase) gene located on the inactive X chromosome in primary and transformed female diploid Chinese hamster cells after treatment with the DNA methylation inhibitor 5-azacytidine (5azaCR). Mutants deficient in HPRT were first selected by growth in 6-thioguanine from two primary fibroblast cell lines and from transformed lines derived from them. These HPRT- mutants were then treated with 5azaCR and plated in HAT (hypoxanthine-methotrexate-thymidine) medium to select for cells that had reexpressed the hprt gene on the inactive X chromosome. Contrary to previous results with primary human cells, 5azaCR was effective in activating the hprt gene in primary Chinese hamster fibroblasts at a low but reproducible frequency of 2 x 10(-6) to 7 x 10(-6). In comparison, the frequency in independently derived transformed lines varied from 1 x 10(-5) to 5 x 10(-3), consistently higher than in the nontransformed cells. This increase remained significant when the difference in growth rates between the primary and transformed lines was taken into account. Treatment with 5azaCR was also found to induce transformation in the primary cell lines but at a low frequency of 4 x 10(-7) to 8 x 10(-7), inconsistent with a two-step model of transformation followed by gene activation to explain the derepression of hprt in primary cells. Thus, these results indicate that upon transformation, the hprt gene on the inactive Chinese hamster X chromosome is rendered more susceptible to action by 5azaCR, consistent with a generalized DNA demethylation associated with the transformation event or with an increase in the instability of an underlying primary mechanism of X inactivation.

scholarly journals Affecting HEK293 Cell Growth and Production Performance by Modifying the Expression of Specific Genes

Cells ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1667
Author(s):  
Laura Abaandou ◽  
David Quan ◽  
Joseph Shiloach
Keyword(s):  
Cell Line ◽  
Cell Lines ◽  
Hek293 Cell ◽  
Chinese Hamster ◽  
Production Performance ◽  
Cellular Processes ◽  
Hek293 Cell Line ◽  
Global Engineering ◽  
Genomic Tools ◽  
Serum Free Suspension

The HEK293 cell line has earned its place as a producer of biotherapeutics. In addition to its ease of growth in serum-free suspension culture and its amenability to transfection, this cell line’s most important attribute is its human origin, which makes it suitable to produce biologics intended for human use. At the present time, the growth and production properties of the HEK293 cell line are inferior to those of non-human cell lines, such as the Chinese hamster ovary (CHO) and the murine myeloma NSO cell lines. However, the modification of genes involved in cellular processes, such as cell proliferation, apoptosis, metabolism, glycosylation, secretion, and protein folding, in addition to bioprocess, media, and vector optimization, have greatly improved the performance of this cell line. This review provides a comprehensive summary of important achievements in HEK293 cell line engineering and on the global engineering approaches and functional genomic tools that have been employed to identify relevant genes for targeted engineering.

scholarly journals Recombinant γY278H Fibrinogen Showed Normal Secretion from CHO Cells, but a Corresponding Heterozygous Patient Showed Hypofibrinogenemia

2021 ◽  
Vol 22 (10) ◽  
pp. 5218
Author(s):  
Tomu Kamijo ◽  
Takahiro Kaido ◽  
Masahiro Yoda ◽  
Shinpei Arai ◽  
Kazuyoshi Yamauchi ◽  
...  
Keyword(s):  
Cell Lines ◽  
Cho Cells ◽  
Fibrinogen Level ◽  
Culture Media ◽  
Chinese Hamster ◽  
Plasma Fibrinogen ◽  
Enzyme Linked Immunosorbent Assay ◽  
Cho Cell ◽  
Accelerated Degradation ◽  
Heterozygous Patient

We identified a novel heterozygous hypofibrinogenemia, γY278H (Hiroshima). To demonstrate the cause of reduced plasma fibrinogen levels (functional level: 1.12 g/L and antigenic level: 1.16 g/L), we established γY278H fibrinogen-producing Chinese hamster ovary (CHO) cells. An enzyme-linked immunosorbent assay demonstrated that synthesis of γY278H fibrinogen inside CHO cells and secretion into the culture media were not reduced. Then, we established an additional five variant fibrinogen-producing CHO cell lines (γL276P, γT277P, γT277R, γA279D, and γY280C) and conducted further investigations. We have already established 33 γ-module variant fibrinogen-producing CHO cell lines, including 6 cell lines in this study, but only the γY278H and γT277R cell lines showed disagreement, namely, recombinant fibrinogen production was not reduced but the patients’ plasma fibrinogen level was reduced. Finally, we performed fibrinogen degradation assays and demonstrated that the γY278H and γT277R fibrinogens were easily cleaved by plasmin whereas their polymerization in the presence of Ca2+ and “D:D” interaction was normal. In conclusion, our investigation suggested that patient γY278H showed hypofibrinogenemia because γY278H fibrinogen was secreted normally from the patient’s hepatocytes but then underwent accelerated degradation by plasmin in the circulation.

scholarly journals Chinese hamster ovary cell line DXB-11: chromosomal instability and karyotype heterogeneity

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Victoria I. Turilova ◽  
Tatyana S. Goryachaya ◽  
Tatiana K. Yakovleva
Keyword(s):  
Cell Line ◽  
Cell Lines ◽  
Chinese Hamster Ovary Cell ◽  
Chinese Hamster Ovary ◽  
Chinese Hamster ◽  
Chromosome 8 ◽  
Ovary Cell ◽  
Differential Staining ◽  
Nucleolar Organizer Regions ◽  
Karyotype Heterogeneity

Abstract Background Chinese hamster ovary cell lines, also known as CHO cells, represent a large family of related, yet quite different, cell lines which are metabolic mutants derived from the original cell line, CHO-ori. Dihydrofolate reductase-deficient DXB-11 cell line, one of the first CHO derivatives, serves as the host cell line for the production of therapeutic proteins. It is generally assumed that DXB-11 is identical to DUKX or CHO-DUK cell lines, but, to our knowledge, DXB-11 karyotype has not been described yet. Results Using differential staining approaches (G-, C-banding and Ag-staining), we presented DXB-11 karyotype and revealed that karyotypes of DXB-11 and CHO-DUK cells have a number of differences. Although the number of chromosomes is equal—20 in each cell line—DXB-11 has normal chromosomes of the 1st and 5th pairs as well as an intact chromosome 8. Besides, in DXB-11 line, chromosome der(Z9) includes the material of chromosomes X and 6, whereas in CHO-DUK it results from the translocation of chromosomes 1 and 6. Ag-positive nucleolar organizer regions were revealed in the long arms of chromosome del(4)(q11q12) and both chromosome 5 homologues, as well as in the short arms of chromosomes 8 and add(8)(q11). Only 19 from 112 (16.96%) DXB-11 cells display identical chromosome complement accepted as the main structural variant of karyotype. The karyotype heterogeneity of all the rest of cells (93, 83.04%) occurs due to clonal and nonclonal additional structural rearrangements of chromosomes. Estimation of the frequency of chromosome involvement in these rearrangements allowed us to reveal that chromosomes 9, der(X)t(X;3;4), del(2)(p21p23), del(2)(q11q22) /Z2, der(4) /Z7, add(6)(p11) /Z8 are the most stable, whereas mar2, probably der(10), is the most unstable chromosome. A comparative analysis of our own and literary data on CHO karyotypes allowed to designate conservative chromosomes, both normal and rearranged, that remain unchanged in different CHO cell lines, as well as variable chromosomes that determine the individuality of karyotypes of CHO derivatives. Conclusion DXB-11and CHO-DUK cell lines differ in karyotypes. The revealed differential instability of DXB-11 chromosomes is likely not incidental and results in karyotype heterogeneity of cell population.

scholarly journals The human TCF-1 gene encodes a nuclear DNA-binding protein uniquely expressed in normal and neoplastic T-lineage lymphocytes

Blood ◽  
1995 ◽  
Vol 86 (8) ◽  
pp. 3050-3059 ◽  
Author(s):  
J Castrop ◽  
D van Wichen ◽  
M Koomans-Bitter ◽  
M van de Wetering ◽  
R de Weger ◽  
...  
Keyword(s):  
T Cell ◽  
Cell Lines ◽  
Nuclear Dna ◽  
Mouse Cell ◽  
Lymphoid Tissues ◽  
Sequence Motif ◽  
Knock Out ◽  
Putative Transcription Factor ◽  
Knock Out Mice ◽  
T Cell Malignancies

Abstract The TCF-1 gene encodes a putative transcription factor with affinity for a sequence motif occurring in a number of T-cell enhancers. TCF-1 mRNA was originally found to be expressed in a T cell-specific fashion within a set of human and mouse cell lines. In contrast, expression reportedly occurs in multiple nonlymphoid tissues during murine embryogenesis. We have now raised a monoclonal antibody to document expression and biochemistry of the human TCF-1 protein. As expected, the TCF-1 protein was detectable only in cell lines of T lineage. Its expression was always restricted to the nucleus. Immunohistochemistry on a panel of human tissues revealed that the TCF-1 protein was found exclusively in thymocytes and in CD3+ T cells in peripheral lymphoid tissues. Western blotting yielded a set of bands ranging from 25 kD to 55 kD, resulting from extensive alternative splicing. The TCF-1 protein was detectable in all samples of a set of 22 T-cell malignancies of various stages of maturation, but was absent from a large number of other hematologic neoplasms. These observations imply a T cell-specific function for TCF-1, a notion corroborated by recent observations on Tcf-1 knock-out mice. In addition, these results indicate that nuclear TCF-1 expression can serve as a pan-T-lineage marker in the diagnosis of lymphoid malignancies.

scholarly journals Functional, Structural, and Distribution Analysis of the Chorionic Gonadotropin Receptor Using Murine Monoclonal Antibodies

2003 ◽  
Vol 88 (11) ◽  
pp. 5537-5546 ◽  
Author(s):  
Ada Funaro ◽  
Anna Sapino ◽  
Bruna Ferranti ◽  
Alberto L. Horenstein ◽  
Isabella Castellano ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Tumor Cell ◽  
Cell Lines ◽  
Chorionic Gonadotropin ◽  
Chinese Hamster Ovary ◽  
Chinese Hamster ◽  
Signal Pathways ◽  
Distribution Analysis ◽  
Tumor Cell Lines ◽  
Transfected Cells

Abstract LH and human chorionic gonadotropin (hCG) control steroid production and gametogenesis. They also function as growth factors through interaction with a specific receptor that is a member of the seven-transmembrane receptor family coupled via G proteins to signal pathways involving cAMP and phospholipase C/inositol 3 phosphate. For this study, monoclonal antibodies (mAbs) were raised against the human LH receptor (LHR)/hCG receptor (hCGR), using Chinese hamster ovary LHR-transfected cells as the immunogen. Two reagents were then selected on the basis of their ability to recognize the full-length transmembrane re-ceptor expressed both by Chinese hamster ovary LHR-transfected cells and by a limited number of tumor cell lines. One of these mAbs reacts with the LHR/hCGR in tissue sections of both frozen and paraffin-embedded specimens. This unique feature allowed us to map the cytological distribution of LHR/hCGR in human breast tissues at different stages of development in physiological and benign pathological conditions. The same mAb proved to be agonistic: receptor ligation elicits signals that modulate the growth of selected breast tumor cell lines. This observation suggests that the mAb recognizes an epitope that is included in the domain of the receptor involved in the interaction with the natural ligand.

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