scholarly journals Multiple 5'-flanking regions of the human alpha-skeletal actin gene synergistically modulate muscle-specific expression.

1987 ◽  
Vol 7 (11) ◽  
pp. 4089-4099 ◽  
Author(s):  
G E Muscat ◽  
L Kedes

Transfection into myogenic and nonmyogenic cell lines was used to investigate the transcriptional regulation of the human alpha-skeletal actin gene. We demonstrated that 1,300 base pairs of the 5'-flanking region directed high-level transient expression of the bacterial chloramphenicol acetyltransferase gene in differentiated mouse C2C12 and rat L8 myotubes but not in mouse nonmuscle L.TK- and HuT-12 cells. Unidirectional 5' deletion analysis and heterologous promoter stimulation experiments demonstrated that at least three transcription-regulating subdomains lie in this 1,300-base-pair region. A proximal cis-acting transcriptional element located between positions -153 and -87 relative to the start of transcription at +1 was both sufficient and necessary for muscle-specific expression and developmental regulation during myogenesis in the two myogenic cell systems. The region 3' of position -87 interacted with factors present in both myogenic and fibroblastic cells and appeared to define, or to be a major component of, the basal promoter. In C2C12 myotubes, but not in L8 myotubes, a distal sequence domain between positions -1300 and -626 and the proximal sequence domain between positions -153 and -87 each induced transcription about 10-fold and synergistically increased CAT expression 100-fold over levels achieved by the sequences 3' of position -87. Furthermore, these cis-acting elements independently and synergistically modulated an enhancerless, heterologous simian virus 40 promoter in a tissue-specific manner. DNA fragments which included the proximal domain displayed classical enhancerlike properties. The central region between positions -626 and -153, although required in neither cell line, had a positive, two- to threefold, additive role in augmenting expression in L8 cells but not in C2C12 cells. This suggests that certain elements between positions -1300 and -153 appear to be differentially utilized for maximal expression in different myogenic cells and that the particular combination of domains used is dependent on the availability, in kind or amount, of trans-acting, transcription-modulating factors present in each cell type. Thus, multiple myogenic factors that vary qualitatively and quantitatively may be responsible for the different and complex modulatory programs of actin gene expression observed during in vivo muscle differentiation.

1987 ◽  
Vol 7 (11) ◽  
pp. 4089-4099
Author(s):  
G E Muscat ◽  
L Kedes

Transfection into myogenic and nonmyogenic cell lines was used to investigate the transcriptional regulation of the human alpha-skeletal actin gene. We demonstrated that 1,300 base pairs of the 5'-flanking region directed high-level transient expression of the bacterial chloramphenicol acetyltransferase gene in differentiated mouse C2C12 and rat L8 myotubes but not in mouse nonmuscle L.TK- and HuT-12 cells. Unidirectional 5' deletion analysis and heterologous promoter stimulation experiments demonstrated that at least three transcription-regulating subdomains lie in this 1,300-base-pair region. A proximal cis-acting transcriptional element located between positions -153 and -87 relative to the start of transcription at +1 was both sufficient and necessary for muscle-specific expression and developmental regulation during myogenesis in the two myogenic cell systems. The region 3' of position -87 interacted with factors present in both myogenic and fibroblastic cells and appeared to define, or to be a major component of, the basal promoter. In C2C12 myotubes, but not in L8 myotubes, a distal sequence domain between positions -1300 and -626 and the proximal sequence domain between positions -153 and -87 each induced transcription about 10-fold and synergistically increased CAT expression 100-fold over levels achieved by the sequences 3' of position -87. Furthermore, these cis-acting elements independently and synergistically modulated an enhancerless, heterologous simian virus 40 promoter in a tissue-specific manner. DNA fragments which included the proximal domain displayed classical enhancerlike properties. The central region between positions -626 and -153, although required in neither cell line, had a positive, two- to threefold, additive role in augmenting expression in L8 cells but not in C2C12 cells. This suggests that certain elements between positions -1300 and -153 appear to be differentially utilized for maximal expression in different myogenic cells and that the particular combination of domains used is dependent on the availability, in kind or amount, of trans-acting, transcription-modulating factors present in each cell type. Thus, multiple myogenic factors that vary qualitatively and quantitatively may be responsible for the different and complex modulatory programs of actin gene expression observed during in vivo muscle differentiation.


1986 ◽  
Vol 6 (11) ◽  
pp. 4130-4132 ◽  
Author(s):  
S Hayashi ◽  
H Kondoh

Expression of the chicken delta-crystallin gene 1 injected into the nuclei of mouse cells is lens specific. Coinjection of GC box-containing DNA fragments from delta-crystallin, simian virus 40 early, and herpes simplex virus type 1 tk promoters effectively suppressed delta-crystallin expression in the lens, but coinjection with DNA fragments not containing the GC box did not. This suppression was likely due to the competition of an Sp1-like transcription factor(s) and indicates involvement of the apparently ubiquitous factor(s) in the tissue-specific expression of the delta-crystallin gene.


1989 ◽  
Vol 9 (10) ◽  
pp. 4581-4584
Author(s):  
J Magram ◽  
K Niederreither ◽  
F Costantini

To examine the role of human beta-globin enhancers in tissue-specific and developmental regulation, a hybrid beta-globin-simian virus 40 gene was analyzed in transgenic mice. A beta-globin DNA fragment containing two previously defined enhancers stimulated transcription from the simian virus 40 promoter in a tissue- and stage-specific pattern similar to that of the normal beta-globin gene. These results help to define the functions of beta-globin regulatory elements and suggest an approach for targeted expression of heterologous genes in erythroid cells in vivo.


1986 ◽  
Vol 6 (11) ◽  
pp. 4130-4132
Author(s):  
S Hayashi ◽  
H Kondoh

Expression of the chicken delta-crystallin gene 1 injected into the nuclei of mouse cells is lens specific. Coinjection of GC box-containing DNA fragments from delta-crystallin, simian virus 40 early, and herpes simplex virus type 1 tk promoters effectively suppressed delta-crystallin expression in the lens, but coinjection with DNA fragments not containing the GC box did not. This suppression was likely due to the competition of an Sp1-like transcription factor(s) and indicates involvement of the apparently ubiquitous factor(s) in the tissue-specific expression of the delta-crystallin gene.


1989 ◽  
Vol 9 (10) ◽  
pp. 4581-4584 ◽  
Author(s):  
J Magram ◽  
K Niederreither ◽  
F Costantini

To examine the role of human beta-globin enhancers in tissue-specific and developmental regulation, a hybrid beta-globin-simian virus 40 gene was analyzed in transgenic mice. A beta-globin DNA fragment containing two previously defined enhancers stimulated transcription from the simian virus 40 promoter in a tissue- and stage-specific pattern similar to that of the normal beta-globin gene. These results help to define the functions of beta-globin regulatory elements and suggest an approach for targeted expression of heterologous genes in erythroid cells in vivo.


1982 ◽  
Vol 2 (12) ◽  
pp. 1595-1607 ◽  
Author(s):  
Timothy J. Miller ◽  
Janet E. Mertz

Purified simian virus 40 (SV40) DNA is reconstituted into chromatin and transcribed by endogenous RNA polymerase II when microinjected into nuclei ofXenopus laevisoocytes. We have correlated the kinetics of chromatin reconstitution with that of accumulation of virus-specific RNA in this system. A delay of approximately 3 h was found in the appearance of appreciable numbers of both fully supercoiled molecules and transcriptionally active templates. SV40 minichromosomes, isolated from virus-infected monkey cells with 0.2 M NaCl, also exhibited this lag in onset of transcriptional activity when microinjected into oocytes. These findings indicate that neither purified SV40 DNA nor SV40 DNA containing a full complement of nucleosomes can function as a template for transcription in vivo before association with appropriate cellular nonhistone chromosomal factors has taken place. In addition, the gradual degradation of linear SV40 DNA in oocytes was not sufficient to account for the fact that it was much less transcriptionally active than circular SV40 DNA. Taken together, these results indicate that the conformational state of the DNA can affect its ability to function as a template for transcription in vivo by RNA polymerase II. In contrast, transcription by RNA polymerase III of purified, circularized cloned DNAs encoding genes for 5S rRNA was detectable long before the injected DNAs had time to reconstitute into chromatin. Therefore, the template structural requirements for transcription in vivo by RNA polymerases II and III are different.


1986 ◽  
Vol 6 (7) ◽  
pp. 2317-2323
Author(s):  
D Zarkower ◽  
P Stephenson ◽  
M Sheets ◽  
M Wickens

The sequence AAUAAA is found near the polyadenylation site of eucaryotic mRNAs. This sequence is required for accurate and efficient cleavage and polyadenylation of pre-mRNAs in vivo. In this study we show that synthetic simian virus 40 late pre-mRNAs are cleaved and polyadenylated in vitro in a HeLa cell nuclear extract, and that cleavage in vitro is abolished by each of four different single-base changes in AAUAAA. In this same extract, precleaved RNAs (RNAs with 3' termini at the polyadenylation site) are efficiently polyadenylated. This in vitro polyadenylation reaction also requires the AAUAAA sequence.


1984 ◽  
Vol 4 (4) ◽  
pp. 813-816
Author(s):  
A Barkan ◽  
J E Mertz

The size distributions of polyribosomes containing each of three simian virus 40 late 16S mRNA species that differ in nucleotide sequence only within their leaders were determined. The two 16S RNA species with shorter leaders were incorporated into polysomes that were both larger (on average) and narrower in size distribution than was the predominant wild-type 16S RNA. Therefore, the nucleotide sequence of the leader can influence the number of ribosomes present on the body of an mRNA molecule. We propose a model in which the excision from leaders of sizeable translatable regions permits more frequent utilization of internally located translation initiation signals, thereby enabling genes encoded within the bodies of polygenic mRNAs to be translated at higher rates. In addition, the data provide the first direct evidence that VP1 can, indeed, be synthesized in vivo from the species of 16S mRNA that also encodes the 61-amino acid leader protein.


1989 ◽  
Vol 9 (6) ◽  
pp. 2378-2386
Author(s):  
L A Neuhold ◽  
Y Shirayoshi ◽  
K Ozato ◽  
J E Jones ◽  
D W Nebert

The mouse cytochrome P1450 (CYP1A1) gene is responsible for the metabolism of numerous carcinogens and toxic chemicals. Induction by the environmental contaminant tetrachlorodibenzo-p-dioxin (TCDD) requires a functional aromatic hydrocarbon (Ah) receptor. We examined the 5'-flanking region of the CYP1A1 gene in mouse hepatoma Hepa-1 wild-type cells and a mutant line having a defect in chromatin binding of the TCDD-receptor complex. We identified two cis-acting elements (distal, -1071 to -901 region; proximal, -245 to -50 region) required for constitutive and TCDD-inducible CYP1A1 gene expression. Three classes of DNA-protein complexes binding to the distal element were identified: class I, found only in the presence of TCDD and a functional Ah receptor, that was heat labile and not competed against by simian virus 40 (SV40) early promoter DNA; class II, consisting of at least three constitutive complexes that were heat stable and bound to SV40 DNA; and class III, composed of at least three constitutive complexes that were thermolabile and were not competed against by SV40 DNA. Essential contacts for these proteins were centered at -993 to -990 for the class I complex, -987, -986, or both for the class II complexes, and -938 to -927 for the class III complexes. The proximal element was absolutely essential for both constitutive and TCDD-inducible CYP1A1 gene expression, and at least two constitutive complexes bound to this region. These data are consistent with the proximal element that binds proteins being necessary but not sufficient for inducible gene expression; interaction of these proteins with those at the distal element was found to be required for full CYP1A1 induction by TCDD.


1988 ◽  
Vol 8 (7) ◽  
pp. 2896-2909 ◽  
Author(s):  
E A Sternberg ◽  
G Spizz ◽  
W M Perry ◽  
D Vizard ◽  
T Weil ◽  
...  

Terminal differentiation of skeletal myoblasts is accompanied by induction of a series of tissue-specific gene products, which includes the muscle isoenzyme of creatine kinase (MCK). To begin to define the sequences and signals involved in MCK regulation in developing muscle cells, the mouse MCK gene has been isolated. Sequence analysis of 4,147 bases of DNA surrounding the transcription initiation site revealed several interesting structural features, some of which are common to other muscle-specific genes and to cellular and viral enhancers. To test for sequences required for regulated expression, a region upstream of the MCK gene from -4800 to +1 base pairs, relative to the transcription initiation site, was linked to the coding sequences of the bacterial chloramphenicol acetyltransferase (CAT) gene. Introduction of this MCK-CAT fusion gene into C2 muscle cells resulted in high-level expression of CAT activity in differentiated myotubes and no detectable expression in proliferating undifferentiated myoblasts or in nonmyogenic cell lines. Deletion mutagenesis of sequences between -4800 and the transcription start site showed that the region between -1351 and -1050 was sufficient to confer cell type-specific and developmentally regulated expression on the MCK promoter. This upstream regulatory element functioned independently of position, orientation, or distance from the promoter and therefore exhibited the properties of a classical enhancer. This upstream enhancer also was able to confer muscle-specific regulation on the simian virus 40 promoter, although it exhibited a 3- to 5-fold preference for its own promoter. In contrast to the cell type- and differentiation-specific expression of the upstream enhancer, the MCK promoter was able to function in myoblasts and myotubes and in nonmyogenic cell lines when combined with the simian virus 40 enhancer. An additional positive regulatory element was identified within the first intron of the MCK gene. Like the upstream enhancer, this intragenic element functioned independently of position, orientation, and distance with respect to the MCK promoter and was active in differentiated myotubes but not in myoblasts. These results demonstrate that expression of the MCK gene in developing muscle cells is controlled by complex interactions among multiple upstream and intragenic regulatory elements that are functional only in the appropriate cellular context.


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