Predominant expression of σ and ε globin genes in human leukemia K-562(S6) variant cell line

Abstract Previous analysis of the hemoglobin phenotype of the K562 human erythroleukemia cell line showed regulated expression of the epsilon-, zeta-, gamma-, alpha-, and delta-globin genes. Expression of the beta- globin genes has not been previously detected in this cell line. In this report, we describe the isolation of a variant of the K562 cell line that actively expresses beta-globin messenger RNA (mRNA) and polypeptide and shows greatly reduced expression of the delta-globin genes. This phenotype developed spontaneously in culture while two other K562 isolates grown under the same culture conditions have not undergone the same delta- to beta-globin switch. Analysis of this unique K562 variant shows that a construct containing a beta-globin promoter is quite active upon transient transfection into these cells. This finding suggests that the activation of the endogenous beta-globin genes results from changes in the trans-acting environment of these cells. The regulation of the beta-globin genes in this variant is characterized by a paradoxical decrease in the level of beta-globin mRNA after exposure to hemin. Other globin genes of this variant are appropriately regulated and show increased expression after hemin induction. Further study of this variant may shed light on mechanisms of gene regulation that are involved in hemoglobin switching.

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Spontaneous delta- to beta-globin switching in K562 human leukemia cells

Blood ◽

10.1182/blood.v79.3.820.bloodjournal793820 ◽

1992 ◽

Vol 79 (3) ◽

pp. 820-825

Author(s):

B Mookerjee ◽

MO Arcasoy ◽

GF Atweh

Keyword(s):

Cell Line ◽

Messenger Rna ◽

Culture Conditions ◽

Human Leukemia ◽

Globin Genes ◽

Beta Globin ◽

Globin Mrna ◽

Hemoglobin Switching ◽

Erythroleukemia Cell ◽

Globin Promoter

Previous analysis of the hemoglobin phenotype of the K562 human erythroleukemia cell line showed regulated expression of the epsilon-, zeta-, gamma-, alpha-, and delta-globin genes. Expression of the beta- globin genes has not been previously detected in this cell line. In this report, we describe the isolation of a variant of the K562 cell line that actively expresses beta-globin messenger RNA (mRNA) and polypeptide and shows greatly reduced expression of the delta-globin genes. This phenotype developed spontaneously in culture while two other K562 isolates grown under the same culture conditions have not undergone the same delta- to beta-globin switch. Analysis of this unique K562 variant shows that a construct containing a beta-globin promoter is quite active upon transient transfection into these cells. This finding suggests that the activation of the endogenous beta-globin genes results from changes in the trans-acting environment of these cells. The regulation of the beta-globin genes in this variant is characterized by a paradoxical decrease in the level of beta-globin mRNA after exposure to hemin. Other globin genes of this variant are appropriately regulated and show increased expression after hemin induction. Further study of this variant may shed light on mechanisms of gene regulation that are involved in hemoglobin switching.

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A Swiss 3T3 variant cell line resistant to the effects of tumor promoters cannot be transformed by src

Molecular and Cellular Biology ◽

10.1128/mcb.10.8.4155-4162.1990 ◽

1990 ◽

Vol 10 (8) ◽

pp. 4155-4162

Author(s):

M Nori ◽

L K Shawver ◽

M J Weber

Keyword(s):

Protein Kinase C ◽

Protein Kinase ◽

Cell Line ◽

Inhibitory Effect ◽

Tumor Promoters ◽

Kinase C ◽

Growth Inhibitory ◽

Variant Cell ◽

Swiss 3T3 ◽

Variant Cell Line

To study the relationship between oncogenesis by v-src and normal cellular signalling pathways, we determined the effects of v-src on 3T3-TNR9 cells, a Swiss 3T3 variant which does not respond mitogenically to tumor promoters such as 12-O-tetradecanoyl-phorbol-13-acetate (TPA). We found that src was unable to transform these variant cells, whether the oncogene was introduced by infection with a murine retrovirus vector or by transfection with plasmid DNA. 3T3-TNR9 cells were not inherently resistant to transformation, since infection with similar recombinant retroviruses containing either v-ras or v-abl did induce transformation. Further analysis of Swiss 3T3 and 3T3-TNR9 cell populations infected with the v-src-containing retrovirus revealed that although the amount of v-src DNA in each was approximately the same, the level of the v-src message and protein and the overall level of phosphotyrosine expressed in the infected variants was much less than in infected parental cells. Cotransfection experiments using separate v-src and neo plasmids revealed a decrease in the number of G418-resistant colonies when transfections of TNR9 cells occurred in the presence of the src-containing plasmid, suggesting a growth inhibitory effect of v-src on 3T3-TNR9 cells, as has also been found for TPA itself. Since v-src cannot transform this variant cell line, which does not respond mitogenically to the protein kinase C agonist TPA, we suggest that src makes use of the protein kinase C pathway as part of its signalling activities.

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Maintained PC1 and PC2 Expression in the AtT-20 Variant Cell Line 6T3 Lacking Regulated Secretion and POMC: Restored POMC Expression and Regulated Secretion after cAMP Treatment

DNA and Cell Biology ◽

10.1089/dna.1995.14.175 ◽

1995 ◽

Vol 14 (2) ◽

pp. 175-188 ◽

Cited By ~ 22

Author(s):

ROBERT DAY ◽

SUZANNE BENJANNET ◽

LINDA MATSUUCHI ◽

REGIS B. KELLY ◽

MIECZYSLAW MARCINKIEWICZ ◽

...

Keyword(s):

Cell Line ◽

Regulated Secretion ◽

Variant Cell ◽

Variant Cell Line

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Differentiation of a mouse neuroblastoma variant cell line whose ornithine decar☐ylase gene has been amplified

Biochimica et Biophysica Acta (BBA) - Molecular Cell Research ◽

10.1016/0167-4889(91)90234-o ◽

1991 ◽

Vol 1133 (1) ◽

pp. 1-8 ◽

Cited By ~ 6

Author(s):

Zong-Ping Chen ◽

Kuang Yu Chen

Keyword(s):

Cell Line ◽

Mouse Neuroblastoma ◽

Variant Cell ◽

Variant Cell Line

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Regulation of the nitrate assimilation pathway of cultured tobacco cells II. Properties of a variant cell line

Biochimica et Biophysica Acta (BBA) - General Subjects ◽

10.1016/0304-4165(70)90398-3 ◽

1970 ◽

Vol 215 (1) ◽

pp. 152-165 ◽

Cited By ~ 62

Author(s):

Y HEIMER ◽

P FILNER

Keyword(s):

Cell Line ◽

Nitrate Assimilation ◽

Tobacco Cells ◽

Variant Cell ◽

Variant Cell Line

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Temperature-sensitive transport of glycoproteins to the surface of a variant mouse lymphoma cell line.

Molecular and Cellular Biology ◽

10.1128/mcb.8.2.833 ◽

1988 ◽

Vol 8 (2) ◽

pp. 833-842 ◽

Cited By ~ 2

Author(s):

M Nori ◽

M R Stallcup

Keyword(s):

Cell Surface ◽

Cell Line ◽

Lymphoma Cell ◽

Response To Treatment ◽

Temperature Sensitive ◽

Lymphoma Cell Line ◽

Wild Type ◽

Variant Cell ◽

Variant Cell Line ◽

Mouse Lymphoma

The expression of mouse mammary tumor virus (MMTV) glycoproteins on the surface of stably infected mouse lymphoma cell line W7MG1 is dramatically increased by glucocorticoid hormones. A variant cell line, W7M.TS1, was selected from W7MG1 for its lack of expression of MMTV glycoproteins on the cell surface in response to treatment with glucocorticoid. Hormonal stimulation of MMTV RNA levels and hormone-induced cytolysis occurred normally in the variant cells. Furthermore, the rates of production of the precursor and mature forms of MMTV glycoproteins in the presence of glucocorticoid were similar in variant and wild-type cells. However, the accumulation of MMTV glycoproteins on the cell surface after hormone treatment was delayed by about 8 h in the variant relative to wild-type cells. The steady-state level of a constitutively expressed cellular protein, T200, on the variant cell surface was comparable to that on wild-type cells. However, in pulse-chase experiments, the appearance of newly synthesized T200 on the cell surface was delayed in the variant compared with wild-type cells. Another glucocorticoid hormone response, removal of H-2 class I antigens from the cell surface, was also delayed in the variant relative to wild-type cells, suggesting that turnover or internalization of cell surface glycoproteins may also be affected in the variant. The defects in the variant cell line were observed at 37 degrees C, but not at 31 degrees C; the variant cells grew normally at both temperatures. This variant phenotype defines a new genetic entity that is important for transport of glycoproteins between internal microsomal compartments and the cell surface.

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