Transient expression of a mouse alpha-fetoprotein minigene: deletion analyses of promoter function

1983 ◽  
Vol 3 (7) ◽  
pp. 1295-1309
Author(s):  
R W Scott ◽  
S M Tilghman
Keyword(s):  
Transient Expression ◽  
Hela Cells ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Alpha Fetoprotein ◽  
Tata Box ◽  
Deletion Mutants ◽  
Promoter Function ◽  
Flanking Region

The constitutive transcription of a mouse alpha-fetoprotein (AFP) minigene was examined during the transient expression of AFP-simian virus 40-pBR322 recombinant DNAs introduced into HeLa cells by Ca3(PO4)2 precipitation. We tested three constructs, each of which contains the AFP minigene and pBR322 DNAs inserted in the late region of simian virus 40 and found that the relative efficiency of AFP gene expression was dependent on the arrangement of the three DNA elements in the vector. The transcripts begin at the authentic AFP cap site and are properly spliced and polyadenylated. To define a sequence domain in the 5' flanking region of the AFP gene required for constitutive expression, sequential 5' deletion mutants of the AFP minigene were constructed and introduced into HeLa cells. All AFP deletion mutants which retained at least the TATA motif located 30 base pairs upstream from the cap site were capable of directing accurate and efficient AFP transcription. However, when the TATA sequence was deleted, no accurately initiated AFP transcripts were detected. These results are identical to those obtained from in vitro transcription of truncated AFP 5' deletion mutant templates assayed in HeLa cell extracts. The rate of AFP transcription in vivo was unaffected by deletion of DNA upstream of the AFP TATA box but was greatly affected by the distance between the simian virus 40 control region and the 5' end of the gene. The absence of any promoter activity upstream of the TATA box in this assay system is in contrast to what has been reported for several other eucaryotic structural genes in a variety of in vivo systems. A sequence comparison between the 5' flanking region of the AFP gene and these genes suggested that the AFP gene lacks those structural elements found to be important for constitutive transcription in vivo. Either the AFP gene lacks upstream promoter function in the 5' flanking DNA contained within the minigene, or the use of a viral vector in a heterologous system precludes its identification.

scholarly journals Transient expression of a mouse alpha-fetoprotein minigene: deletion analyses of promoter function.

1983 ◽  
Vol 3 (7) ◽  
pp. 1295-1309 ◽  
Author(s):  
R W Scott ◽  
S M Tilghman
Keyword(s):  
Transient Expression ◽  
Hela Cells ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Alpha Fetoprotein ◽  
Tata Box ◽  
Deletion Mutants ◽  
Promoter Function ◽  
Flanking Region

The constitutive transcription of a mouse alpha-fetoprotein (AFP) minigene was examined during the transient expression of AFP-simian virus 40-pBR322 recombinant DNAs introduced into HeLa cells by Ca3(PO4)2 precipitation. We tested three constructs, each of which contains the AFP minigene and pBR322 DNAs inserted in the late region of simian virus 40 and found that the relative efficiency of AFP gene expression was dependent on the arrangement of the three DNA elements in the vector. The transcripts begin at the authentic AFP cap site and are properly spliced and polyadenylated. To define a sequence domain in the 5' flanking region of the AFP gene required for constitutive expression, sequential 5' deletion mutants of the AFP minigene were constructed and introduced into HeLa cells. All AFP deletion mutants which retained at least the TATA motif located 30 base pairs upstream from the cap site were capable of directing accurate and efficient AFP transcription. However, when the TATA sequence was deleted, no accurately initiated AFP transcripts were detected. These results are identical to those obtained from in vitro transcription of truncated AFP 5' deletion mutant templates assayed in HeLa cell extracts. The rate of AFP transcription in vivo was unaffected by deletion of DNA upstream of the AFP TATA box but was greatly affected by the distance between the simian virus 40 control region and the 5' end of the gene. The absence of any promoter activity upstream of the TATA box in this assay system is in contrast to what has been reported for several other eucaryotic structural genes in a variety of in vivo systems. A sequence comparison between the 5' flanking region of the AFP gene and these genes suggested that the AFP gene lacks those structural elements found to be important for constitutive transcription in vivo. Either the AFP gene lacks upstream promoter function in the 5' flanking DNA contained within the minigene, or the use of a viral vector in a heterologous system precludes its identification.

scholarly journals Simian virus 40 major late promoter: a novel tripartite structure that includes intragenic sequences.

1988 ◽  
Vol 8 (5) ◽  
pp. 2021-2033 ◽  
Author(s):  
D E Ayer ◽  
W S Dynan
Keyword(s):  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Point Mutations ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Transcription Unit ◽  
Tata Box ◽  
Base Pairs

Unlike most genes transcribed by RNA polymerase II, the simian virus 40 late transcription unit does not have a TATA box. To determine what sequences are required for initiation at the major late mRNA cap site of simian virus 40, clustered point mutations were constructed and tested for transcriptional activity in vitro and in vivo. Three promoter elements were defined. The first is centered 31 base pairs upstream of the cap site in a position normally reserved for a TATA box. The second is at the cap site. The third occupies a novel position centered 28 base pairs downstream of the cap site within a protein-coding sequence. The ability of RNA polymerase II to recognize this promoter suggests that there is greater variation in promoter architecture than had been believed previously.

Simian virus 40 major late promoter: a novel tripartite structure that includes intragenic sequences

1988 ◽  
Vol 8 (5) ◽  
pp. 2021-2033
Author(s):  
D E Ayer ◽  
W S Dynan
Keyword(s):  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Point Mutations ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Transcription Unit ◽  
Tata Box ◽  
Base Pairs

Unlike most genes transcribed by RNA polymerase II, the simian virus 40 late transcription unit does not have a TATA box. To determine what sequences are required for initiation at the major late mRNA cap site of simian virus 40, clustered point mutations were constructed and tested for transcriptional activity in vitro and in vivo. Three promoter elements were defined. The first is centered 31 base pairs upstream of the cap site in a position normally reserved for a TATA box. The second is at the cap site. The third occupies a novel position centered 28 base pairs downstream of the cap site within a protein-coding sequence. The ability of RNA polymerase II to recognize this promoter suggests that there is greater variation in promoter architecture than had been believed previously.

scholarly journals Template Structural Requirements for Transcription In Vivo by RNA Polymerase II

1982 ◽  
Vol 2 (12) ◽  
pp. 1595-1607 ◽  
Author(s):  
Timothy J. Miller ◽  
Janet E. Mertz
Keyword(s):  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Rna Polymerase Iii ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Structural Requirements ◽  
Infected Monkey ◽  
Full Complement ◽  
Sv40 Dna

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.

scholarly journals In vivo competition of delta-crystallin gene expression by DNA fragments containing a GC box.

1986 ◽  
Vol 6 (11) ◽  
pp. 4130-4132 ◽  
Author(s):  
S Hayashi ◽  
H Kondoh
Keyword(s):  
Gene Expression ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Dna Fragments ◽  
Specific Expression ◽  
Mouse Cells ◽  
Gc Box ◽  
Simplex Virus

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.

The AAUAAA sequence is required both for cleavage and for polyadenylation of simian virus 40 pre-mRNA in vitro

1986 ◽  
Vol 6 (7) ◽  
pp. 2317-2323
Author(s):  
D Zarkower ◽  
P Stephenson ◽  
M Sheets ◽  
M Wickens
Keyword(s):  
Hela Cell ◽  
Simian Virus 40 ◽  
Nuclear Extract ◽  
Simian Virus ◽  
Polyadenylation Site ◽  
Single Base ◽  
Cleavage And Polyadenylation ◽  
Cell Nuclear Extract

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.

The number of ribosomes on simian virus 40 late 16S mRNA is determined in part by the nucleotide sequence of its leader

1984 ◽  
Vol 4 (4) ◽  
pp. 813-816
Author(s):  
A Barkan ◽  
J E Mertz
Keyword(s):  
Nucleotide Sequence ◽  
Direct Evidence ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
The Body ◽  
Size Distributions ◽  
Wild Type ◽  
Leader Protein ◽  
16S Rna

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.

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