scholarly journals Regulated expression of a transfected human cardiac actin gene during differentiation of multipotential murine embryonal carcinoma cells.

1988 ◽  
Vol 8 (1) ◽  
pp. 406-417 ◽  
Author(s):  
M A Rudnicki ◽  
M Ruben ◽  
M W McBurney
Keyword(s):  
Cardiac Muscle ◽  
Thymidine Kinase ◽  
Embryonal Carcinoma ◽  
Actin Gene ◽  
P19 Cells ◽  
Cardiac Muscle Cells ◽  
Cardiac Actin ◽  
Ec Cells ◽  
Actin Promoter ◽  
Actin Mrna

P19 embryonal carcinoma (EC) cells are multipotential stem cells which can be induced to differentiate in vitro into a variety of cell types, including cardiac muscle cells. A cloned human cardiac actin (CH-actin) gene was transfected into P19 cells, and stable transformants were isolated. Low levels of CH-actin mRNA were present in transformed EC cells, but a marked increase in the level of CH-actin mRNA was found as these cells differentiated into cardiac muscle. The accumulation of CH-actin mRNA paralleled that of the endogenous mouse cardiac actin mRNA. A chimeric gene, which consisted of the CH-actin promoter linked to the herpes simplex virus thymidine kinase coding region, was constructed and transfected into P19 cells. In these transformants, the thymidine kinase protein was located almost exclusively in cardiac muscle cells and was generally not detectable in EC or other nonmuscle cells. These results suggest that the transfected CH-actin promoter functions in the appropriate developmental and tissue-specific manner during the differentiation of multipotential EC cells in culture.

Regulated expression of a transfected human cardiac actin gene during differentiation of multipotential murine embryonal carcinoma cells

1988 ◽  
Vol 8 (1) ◽  
pp. 406-417
Author(s):  
M A Rudnicki ◽  
M Ruben ◽  
M W McBurney
Keyword(s):  
Cardiac Muscle ◽  
Thymidine Kinase ◽  
Embryonal Carcinoma ◽  
Actin Gene ◽  
P19 Cells ◽  
Cardiac Muscle Cells ◽  
Cardiac Actin ◽  
Ec Cells ◽  
Actin Promoter ◽  
Actin Mrna

P19 embryonal carcinoma (EC) cells are multipotential stem cells which can be induced to differentiate in vitro into a variety of cell types, including cardiac muscle cells. A cloned human cardiac actin (CH-actin) gene was transfected into P19 cells, and stable transformants were isolated. Low levels of CH-actin mRNA were present in transformed EC cells, but a marked increase in the level of CH-actin mRNA was found as these cells differentiated into cardiac muscle. The accumulation of CH-actin mRNA paralleled that of the endogenous mouse cardiac actin mRNA. A chimeric gene, which consisted of the CH-actin promoter linked to the herpes simplex virus thymidine kinase coding region, was constructed and transfected into P19 cells. In these transformants, the thymidine kinase protein was located almost exclusively in cardiac muscle cells and was generally not detectable in EC or other nonmuscle cells. These results suggest that the transfected CH-actin promoter functions in the appropriate developmental and tissue-specific manner during the differentiation of multipotential EC cells in culture.

scholarly journals Multiple CArG boxes in the human cardiac actin gene promoter required for expression in embryonic cardiac muscle cells developing in vitro from embryonal carcinoma cells.

1991 ◽  
Vol 11 (9) ◽  
pp. 4796-4803 ◽  
Author(s):  
G Pari ◽  
K Jardine ◽  
M W McBurney
Keyword(s):  
Cardiac Muscle ◽  
Embryonal Carcinoma ◽  
Core Promoter ◽  
Carcinoma Cells ◽  
Regulatory Sequences ◽  
Embryonal Carcinoma Cells ◽  
Cardiac Muscle Cells ◽  
Cardiac Actin ◽  
Actin Promoter

Chimeric genes composed of the human cardiac actin promoter driving the Escherichia coli lacZ reporter gene were constructed, transfected, and stably integrated into genomes of P19 embryonal carcinoma cells. The transfected constructs were expressed actively in cardiac myocytes formed following dimethyl sulfoxide (DMSO)-induced cell differentiation but poorly in undifferentiated cultures and in cultures treated with retinoic acid to develop into derivatives of the neuroectoderm. A number of deletions of the promoter were constructed and tested. Three regions required for efficient expression in P19-derived cardiac muscle were identified, each containing sequences referred to as CArG boxes (CC[AT-rich]6GG). This analysis indicated that regulatory sequences important for expression in cardiac muscle were present upstream of the core promoter identified previously by transient assays in skeletal myoblasts. Expression of the cardiac actin promoter was enhanced 10-fold in undifferentiated P19 cells in the presence of the myoD protein. The promoter regions important for expression in P19-derived cardiocytes were similar to those important for myoD-induced enhancement, a result we interpret to be consistent with the idea that cardiac muscle might contain a myoD-like activity.

Multiple CArG boxes in the human cardiac actin gene promoter required for expression in embryonic cardiac muscle cells developing in vitro from embryonal carcinoma cells

1991 ◽  
Vol 11 (9) ◽  
pp. 4796-4803
Author(s):  
G Pari ◽  
K Jardine ◽  
M W McBurney
Keyword(s):  
Cardiac Muscle ◽  
Embryonal Carcinoma ◽  
Core Promoter ◽  
Carcinoma Cells ◽  
Regulatory Sequences ◽  
Embryonal Carcinoma Cells ◽  
Cardiac Muscle Cells ◽  
Cardiac Actin ◽  
Actin Promoter

Chimeric genes composed of the human cardiac actin promoter driving the Escherichia coli lacZ reporter gene were constructed, transfected, and stably integrated into genomes of P19 embryonal carcinoma cells. The transfected constructs were expressed actively in cardiac myocytes formed following dimethyl sulfoxide (DMSO)-induced cell differentiation but poorly in undifferentiated cultures and in cultures treated with retinoic acid to develop into derivatives of the neuroectoderm. A number of deletions of the promoter were constructed and tested. Three regions required for efficient expression in P19-derived cardiac muscle were identified, each containing sequences referred to as CArG boxes (CC[AT-rich]6GG). This analysis indicated that regulatory sequences important for expression in cardiac muscle were present upstream of the core promoter identified previously by transient assays in skeletal myoblasts. Expression of the cardiac actin promoter was enhanced 10-fold in undifferentiated P19 cells in the presence of the myoD protein. The promoter regions important for expression in P19-derived cardiocytes were similar to those important for myoD-induced enhancement, a result we interpret to be consistent with the idea that cardiac muscle might contain a myoD-like activity.

scholarly journals Cellular localization of muscle and nonmuscle actin mRNAs in chicken primary myogenic cultures: the induction of alpha-skeletal actin mRNA is regulated independently of alpha-cardiac actin gene expression.

1988 ◽  
Vol 106 (6) ◽  
pp. 2077-2086 ◽  
Author(s):  
L J Hayward ◽  
Y Y Zhu ◽  
R J Schwartz
Keyword(s):  
Cellular Localization ◽  
Myoblast Fusion ◽  
Bipolar Cells ◽  
Gene Probe ◽  
Actin Gene ◽  
Cardiac Actin ◽  
Beta Actin ◽  
Hybridization Probes ◽  
Muscle Cultures ◽  
Actin Mrna

Specific DNA fragments complementary to the 3' untranslated regions of the beta-, alpha-cardiac, and alpha-skeletal actin mRNAs were used as in situ hybridization probes to examine differential expression and distribution of these mRNAs in primary myogenic cultures. We demonstrated that prefusion bipolar-shaped cells derived from day 3 dissociated embryonic somites were equivalent to myoblasts derived from embryonic day 11-12 pectoral tissue with respect to the expression of the alpha-cardiac actin gene. Fibroblasts present in primary muscle cultures were not labeled by the alpha-cardiac actin gene probe. Since virtually all of the bipolar cells express alpha-cardiac actin mRNA before fusion, we suggest that the bipolar phenotype may distinguish a committed myogenic cell type. In contrast, alpha-skeletal actin mRNA accumulates only in multinucleated myotubes and appears to be regulated independently from the alpha-cardiac actin gene. Accumulation of alpha-skeletal but not alpha-cardiac actin mRNA can be blocked by growth in Ca2+-deficient medium which arrests myoblast fusion. Thus, the sequential appearance of alpha-cardiac and then alpha-skeletal actin mRNA may result from factors that arise during terminal differentiation. Finally, the beta-actin mRNA was located in both fibroblasts and myoblasts but diminished in content during myoblast fusion and was absent from differentiated myotubes. It appears that in primary myogenic cultures, an asynchronous stage-dependent induction of two different alpha-striated actin mRNA species occurs concomitant with the deinduction of the nonmuscle beta-actin gene.

Dominant negative retinoid X receptor beta inhibits retinoic acid-responsive gene regulation in embryonal carcinoma cells

1994 ◽  
Vol 14 (1) ◽  
pp. 360-372
Author(s):  
S Minucci ◽  
D J Zand ◽  
A Dey ◽  
M S Marks ◽  
T Nagata ◽  
...  
Keyword(s):  
Gene Regulation ◽  
Retinoic Acid ◽  
Embryonal Carcinoma ◽  
Hormone Receptors ◽  
Binding Activity ◽  
Dominant Negative ◽  
P19 Cells ◽  
Mobility Shift ◽  
Ec Cells ◽  
Dominant Negative Activity

Retinoid X receptors (RXRs) heterodimerize with multiple nuclear hormone receptors and are thought to exert pleiotropic functions. To address the role of RXRs in retinoic acid- (RA) mediated gene regulation, we designed a dominant negative RXR beta. This mutated receptor, termed DBD-, lacked the DNA binding domain but retained the ability to dimerize with partner receptors, resulting in formation of nonfunctional dimers. DBD- was transfected into P19 murine embryonal carcinoma (EC) cells, in which reporters containing the RA-responsive elements (RAREs) were activated by RA through the activity of endogenous RXR-RA receptor (RAR) heterodimers. We found that DBD- had a dominant negative activity on the RARE reporter activity in these cells. P19 clones stably expressing DBD- were established; these clones also failed to activate RARE-driven reporters in response to RA. Further, these cells were defective in RA-induced mRNA expression of Hox-1.3 and RAR beta, as well as in RA-induced down-regulation of Oct3 mRNA. Gel mobility shift assays demonstrated that RA treatment of control P19 cells induces RARE-binding activity, of which RXR beta is a major component. However, the RA-induced binding activity was greatly reduced in cells expressing DBD-. By genomic footprinting, we show that RA treatment induces in vivo occupancy of the RARE in the endogenous RAR beta gene in control P19 cells but that this occupancy is not observed with the DBD- cells. These data provide evidence that the dominant negative activity of DBD- is caused by the lack of receptor binding to target DNA. Finally, we show that in F9 EC cells expression of DBD- leads to inhibition of the growth arrest that accompanies RA-induced differentiation. Taken together, these results demonstrate that RXR beta and partner receptors play a central role in RA-mediated gene regulation and in the control of growth and differentiation in EC cells.

scholarly journals alpha-skeletal and alpha-cardiac actin genes are coexpressed in adult human skeletal muscle and heart.

1983 ◽  
Vol 3 (11) ◽  
pp. 1985-1995 ◽  
Author(s):  
P Gunning ◽  
P Ponte ◽  
H Blau ◽  
L Kedes
Keyword(s):  
Skeletal Muscle ◽  
Smooth Muscle ◽  
Human Skeletal Muscle ◽  
Cdna Clones ◽  
Actin Gene ◽  
Adult Heart ◽  
Adult Human ◽  
Actin Genes ◽  
Cardiac Actin ◽  
Actin Mrna

We determined the actin isotypes encoded by 30 actin cDNA clones previously isolated from an adult human muscle cDNA library. Using 3' untranslated region probes derived from alpha-skeletal, beta- and gamma-actin cDNAs and from an alpha-cardiac actin genomic clone, we showed that 28 of the cDNAs correspond to alpha-skeletal actin transcripts. Unexpectedly, however, the remaining two cDNA clones proved to derive from alpha-cardiac actin mRNA. Sequence analysis confirmed that the two skeletal muscle alpha-cardiac actin cDNAs are derived from transcripts of the cloned alpha-cardiac actin gene. Direct measurements of actin isotype mRNA expression in human skeletal muscle showed that alpha-cardiac actin mRNA is expressed at 5% the level of alpha-skeletal actin. Furthermore, the alpha-cardiac actin gene expressed in skeletal muscle is the same gene which produces alpha-cardiac actin mRNA in the human heart. Of equal surprise, we found that alpha-skeletal actin mRNA accounts for about half of the total actin mRNA in adult heart. Comparison of total actin mRNA levels in adult skeletal muscle and adult heart revealed that the steady-state levels in skeletal muscle are about twofold greater, per microgram of total cellular RNA, than those in heart. Thus, in skeletal muscle and in heart, both of the sarcomeric actin mRNA isotypes are quite abundant transcripts. We conclude that alpha-skeletal and alpha-cardiac actin genes are coexpressed as an actin pair in human adult striated muscles. Since the smooth-muscle actins (aortic and stomach) and the cytoplasmic actins (beta and gamma) are known to be coexpressed in smooth muscle and nonmuscle cells, respectively, we postulate that coexpression of actin pairs may be a common feature of mammalian actin gene expression in all tissues.

scholarly journals Dominant negative retinoid X receptor beta inhibits retinoic acid-responsive gene regulation in embryonal carcinoma cells.

1994 ◽  
Vol 14 (1) ◽  
pp. 360-372 ◽  
Author(s):  
S Minucci ◽  
D J Zand ◽  
A Dey ◽  
M S Marks ◽  
T Nagata ◽  
...  
Keyword(s):  
Gene Regulation ◽  
Retinoic Acid ◽  
Embryonal Carcinoma ◽  
Hormone Receptors ◽  
Binding Activity ◽  
Dominant Negative ◽  
P19 Cells ◽  
Mobility Shift ◽  
Ec Cells ◽  
Dominant Negative Activity

Retinoid X receptors (RXRs) heterodimerize with multiple nuclear hormone receptors and are thought to exert pleiotropic functions. To address the role of RXRs in retinoic acid- (RA) mediated gene regulation, we designed a dominant negative RXR beta. This mutated receptor, termed DBD-, lacked the DNA binding domain but retained the ability to dimerize with partner receptors, resulting in formation of nonfunctional dimers. DBD- was transfected into P19 murine embryonal carcinoma (EC) cells, in which reporters containing the RA-responsive elements (RAREs) were activated by RA through the activity of endogenous RXR-RA receptor (RAR) heterodimers. We found that DBD- had a dominant negative activity on the RARE reporter activity in these cells. P19 clones stably expressing DBD- were established; these clones also failed to activate RARE-driven reporters in response to RA. Further, these cells were defective in RA-induced mRNA expression of Hox-1.3 and RAR beta, as well as in RA-induced down-regulation of Oct3 mRNA. Gel mobility shift assays demonstrated that RA treatment of control P19 cells induces RARE-binding activity, of which RXR beta is a major component. However, the RA-induced binding activity was greatly reduced in cells expressing DBD-. By genomic footprinting, we show that RA treatment induces in vivo occupancy of the RARE in the endogenous RAR beta gene in control P19 cells but that this occupancy is not observed with the DBD- cells. These data provide evidence that the dominant negative activity of DBD- is caused by the lack of receptor binding to target DNA. Finally, we show that in F9 EC cells expression of DBD- leads to inhibition of the growth arrest that accompanies RA-induced differentiation. Taken together, these results demonstrate that RXR beta and partner receptors play a central role in RA-mediated gene regulation and in the control of growth and differentiation in EC cells.

Regulation of a human cardiac actin gene introduced into rat L6 myoblasts suggests a defect in their myogenic program

1986 ◽  
Vol 6 (9) ◽  
pp. 3287-3290
Author(s):  
R Hickey ◽  
A Skoultchi ◽  
P Gunning ◽  
L Kedes
Keyword(s):  
Gene Expression ◽  
Cell Line ◽  
Human Gene ◽  
Actin Gene ◽  
Cardiac Actin ◽  
Gene Transcripts ◽  
Actin Mrna ◽  
Muscle Gene ◽  
Alpha Actin ◽  
Myogenic Program

The rat myogenic cell line L6E9 induces skeletal but not cardiac alpha-actin mRNA upon fusion to form myotubes. However, when a human cardiac alpha-actin gene was introduced into L6E9 myoblasts, differentiation of the cells led to the accumulation of human gene transcripts in parallel with those derived from the endogenous skeletal alpha-actin gene. This result demonstrates that factors which direct rat myogenesis can regulate a muscle gene from another species and that the L6E9 cells may have a defect in their ability to activate endogenous cardiac actin gene expression.

A transfected H-ras oncogene does not inhibit differentiation of cardiac and skeletal muscle from embryonal carcinoma cells

1989 ◽  
Vol 67 (9) ◽  
pp. 590-596 ◽  
Author(s):  
Michael A. Rudnicki ◽  
Kenneth R. Reuhl ◽  
Michael W. McBurney
Keyword(s):  
Skeletal Muscle ◽  
Cell Lines ◽  
Embryonal Carcinoma ◽  
Cell Types ◽  
P19 Cells ◽  
Ras Oncogene ◽  
Specific Expression ◽  
Ec Cells ◽  
Myoblast Cell

P19 embryonal carcinoma (EC) cells can be induced to differentiate in vitro into a variety of cell types, including cardiac and skeletal myocytes. We have isolated P19 cells stably transformed with either the activated human H-ras oncogene or with a chimeric gene in which the H-ras oncogene was controlled by a muscle-specific promoter. These P19 lines exhibited ubiquitous and muscle-specific expression of the activated H-ras protein, respectively. In both lines of P19 cells, normal cardiac and skeletal muscle differentiation was observed. Since the activated H-ras prevents differentiation of myoblast cell lines, our results suggest that the EC-derived muscle progenitor cell differs from continuous myoblast cell lines, perhaps by lacking a complementing oncogene responsible for myoblast immortalization.Key words: embryonal carcinoma, oncogene, ras, differentiation, myogenesis.

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