Abstract
The 5'-flanking DNA sequences involved in the specific and efficient transcription of the polyoma virus early region have been investigated. Sequence requirements for efficient in vivo expression differed from those in vitro. Deletion of DNA located between 200 and 400 base pairs before the principal cap sites severely inhibited in vivo expression as measured by transformation ability, but did not affect in vitro transcription. Viable deletion mutants which lack the principal cap sites and the "TATA" box were very poor templates for in vitro transcription. Analysis of other deletion mutants in vitro demonstrated that no specific sequences more than 46 base pairs before the cap sites were important. Removal of the TATA box reduced in vitro transcriptional efficiency but did not alter the initiation sites. The synthesis of transcripts with abnormal 5' termini did not occur in vitro until sequence between the TATA box and the normal cap sites was also deleted. We further observed a nonspecific requirement for 90 to 100 base pairs of DNA 5' to the cap site for optimal transcription of DNA fragments in vitro.
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Selected References
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- Baker C. C., Ziff E. B. Promoters and heterogeneous 5' termini of the messenger RNAs of adenovirus serotype 2. J Mol Biol. 1981 Jun 25;149(2):189–221. doi: 10.1016/0022-2836(81)90298-9. [DOI] [PubMed] [Google Scholar]
- Banerji J., Rusconi S., Schaffner W. Expression of a beta-globin gene is enhanced by remote SV40 DNA sequences. Cell. 1981 Dec;27(2 Pt 1):299–308. doi: 10.1016/0092-8674(81)90413-x. [DOI] [PubMed] [Google Scholar]
- Bendig M. M., Folk W. R. Deletion mutants of polyoma virus defining a nonessential region between the origin of replication and the initiation codon for early proteins. J Virol. 1979 Nov;32(2):530–535. doi: 10.1128/jvi.32.2.530-535.1979. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bendig M. M., Thomas T., Folk W. R. Regulatory mutants of polyoma virus defective in DNA replication and the synthesis of early proteins. Cell. 1980 Jun;20(2):401–409. doi: 10.1016/0092-8674(80)90626-1. [DOI] [PubMed] [Google Scholar]
- Benoist C., Chambon P. Deletions covering the putative promoter region of early mRNAs of simian virus 40 do not abolish T-antigen expression. Proc Natl Acad Sci U S A. 1980 Jul;77(7):3865–3869. doi: 10.1073/pnas.77.7.3865. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Benoist C., Chambon P. In vivo sequence requirements of the SV40 early promotor region. Nature. 1981 Mar 26;290(5804):304–310. doi: 10.1038/290304a0. [DOI] [PubMed] [Google Scholar]
- Benoist C., O'Hare K., Breathnach R., Chambon P. The ovalbumin gene-sequence of putative control regions. Nucleic Acids Res. 1980 Jan 11;8(1):127–142. doi: 10.1093/nar/8.1.127. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Berk A. J., Sharp P. A. Sizing and mapping of early adenovirus mRNAs by gel electrophoresis of S1 endonuclease-digested hybrids. Cell. 1977 Nov;12(3):721–732. doi: 10.1016/0092-8674(77)90272-0. [DOI] [PubMed] [Google Scholar]
- Birnboim H. C., Doly J. A rapid alkaline extraction procedure for screening recombinant plasmid DNA. Nucleic Acids Res. 1979 Nov 24;7(6):1513–1523. doi: 10.1093/nar/7.6.1513. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Boyer H. W., Roulland-Dussoix D. A complementation analysis of the restriction and modification of DNA in Escherichia coli. J Mol Biol. 1969 May 14;41(3):459–472. doi: 10.1016/0022-2836(69)90288-5. [DOI] [PubMed] [Google Scholar]
- Breathnach R., Chambon P. Organization and expression of eucaryotic split genes coding for proteins. Annu Rev Biochem. 1981;50:349–383. doi: 10.1146/annurev.bi.50.070181.002025. [DOI] [PubMed] [Google Scholar]
- Cogen B. Virus-specific early RNA in 3T6 cells infected by a tsA mutant of polyoma virus. Virology. 1978 Mar;85(1):222–230. doi: 10.1016/0042-6822(78)90426-9. [DOI] [PubMed] [Google Scholar]
- Corden J., Wasylyk B., Buchwalder A., Sassone-Corsi P., Kedinger C., Chambon P. Promoter sequences of eukaryotic protein-coding genes. Science. 1980 Sep 19;209(4463):1406–1414. doi: 10.1126/science.6251548. [DOI] [PubMed] [Google Scholar]
- Cowie A., Tyndall C., Kamen R. Sequences at the capped 5'-ends of polyoma virus late region mRNAs: an example of extreme terminal heterogeneity. Nucleic Acids Res. 1981 Dec 11;9(23):6305–6322. doi: 10.1093/nar/9.23.6305. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Dierks P., van Ooyen A., Mantei N., Weissmann C. DNA sequences preceding the rabbit beta-globin gene are required for formation in mouse L cells of beta-globin RNA with the correct 5' terminus. Proc Natl Acad Sci U S A. 1981 Mar;78(3):1411–1415. doi: 10.1073/pnas.78.3.1411. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Efstratiadis A., Posakony J. W., Maniatis T., Lawn R. M., O'Connell C., Spritz R. A., DeRiel J. K., Forget B. G., Weissman S. M., Slightom J. L. The structure and evolution of the human beta-globin gene family. Cell. 1980 Oct;21(3):653–668. doi: 10.1016/0092-8674(80)90429-8. [DOI] [PubMed] [Google Scholar]
- FRIED M. ISOLATION OF TEMPERATURE-SENSITIVE MUTANTS OF POLYOMA VIRUS. Virology. 1965 Apr;25:669–671. doi: 10.1016/0042-6822(65)90098-x. [DOI] [PubMed] [Google Scholar]
- Favaloro J., Treisman R., Kamen R. Transcription maps of polyoma virus-specific RNA: analysis by two-dimensional nuclease S1 gel mapping. Methods Enzymol. 1980;65(1):718–749. doi: 10.1016/s0076-6879(80)65070-8. [DOI] [PubMed] [Google Scholar]
- Faye G., Leung D. W., Tatchell K., Hall B. D., Smith M. Deletion mapping of sequences essential for in vivo transcription of the iso-1-cytochrome c gene. Proc Natl Acad Sci U S A. 1981 Apr;78(4):2258–2262. doi: 10.1073/pnas.78.4.2258. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Freeman A. E., Gilden R. V., Vernon M. L., Wolford R. G., Hugunin P. E., Huebner R. J. 5-Bromo-2'-deoxyuridine potentiation of transformation of rat-embryo cells induced in vitro by 3-methylcholanthrene: induction of rat leukemia virus gs antigen in transformed cells. Proc Natl Acad Sci U S A. 1973 Aug;70(8):2415–2419. doi: 10.1073/pnas.70.8.2415. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ghosh P. K., Lebowitz P., Frisque R. J., Gluzman Y. Identification of a promoter component involved in positioning the 5' termini of simian virus 40 early mRNAs. Proc Natl Acad Sci U S A. 1981 Jan;78(1):100–104. doi: 10.1073/pnas.78.1.100. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ghosh P. K., Reddy V. B., Piatak M., Lebowitz P., Weissman S. M. Determination of RNA sequences by primer directed synthesis and sequencing of their cDNA transcripts. Methods Enzymol. 1980;65(1):580–595. doi: 10.1016/s0076-6879(80)65061-7. [DOI] [PubMed] [Google Scholar]
- Gluzman Y., Sambrook J. F., Frisque R. J. Expression of early genes of origin-defective mutants of simian virus 40. Proc Natl Acad Sci U S A. 1980 Jul;77(7):3898–3902. doi: 10.1073/pnas.77.7.3898. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Griffin B. E., Fried M., Cowie A. Polyoma DNA: a physical map. Proc Natl Acad Sci U S A. 1974 May;71(5):2077–2081. doi: 10.1073/pnas.71.5.2077. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Grosschedl R., Birnstiel M. L. Identification of regulatory sequences in the prelude sequences of an H2A histone gene by the study of specific deletion mutants in vivo. Proc Natl Acad Sci U S A. 1980 Mar;77(3):1432–1436. doi: 10.1073/pnas.77.3.1432. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Grosschedl R., Birnstiel M. L. Spacer DNA sequences upstream of the T-A-T-A-A-A-T-A sequence are essential for promotion of H2A histone gene transcription in vivo. Proc Natl Acad Sci U S A. 1980 Dec;77(12):7102–7106. doi: 10.1073/pnas.77.12.7102. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Grosveld G. C., Shewmaker C. K., Jat P., Flavell R. A. Localization of DNA sequences necessary for transcription of the rabbit beta-globin gene in vitro. Cell. 1981 Jul;25(1):215–226. doi: 10.1016/0092-8674(81)90246-4. [DOI] [PubMed] [Google Scholar]
- Hagenbüchle O., Schibler U. Mouse beta-globin and adenovirus-2 major late transcripts are initiated at the cap site in vitro. Proc Natl Acad Sci U S A. 1981 Apr;78(4):2283–2286. doi: 10.1073/pnas.78.4.2283. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Handa H., Kaufman R. J., Manley J., Gefter M., Sharp P. A. Transcription of Simian virus 40 DNA in a HeLa whole cell extract. J Biol Chem. 1981 Jan 10;256(1):478–482. [PubMed] [Google Scholar]
- Hansen U., Tenen D. G., Livingston D. M., Sharp P. A. T antigen repression of SV40 early transcription from two promoters. Cell. 1981 Dec;27(3 Pt 2):603–613. doi: 10.1016/0092-8674(81)90402-5. [DOI] [PubMed] [Google Scholar]
- Hentschel C. C., Birnstiel M. L. The organization and expression of histone gene families. Cell. 1981 Aug;25(2):301–313. doi: 10.1016/0092-8674(81)90048-9. [DOI] [PubMed] [Google Scholar]
- Hu S. L., Manley J. L. DNA sequence required for initiation of transcription in vitro from the major late promoter of adenovirus 2. Proc Natl Acad Sci U S A. 1981 Feb;78(2):820–824. doi: 10.1073/pnas.78.2.820. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Jat P., Roberts J. W., Cowie A., Kamen R. Comparison of the polyoma virus early and late promoters by transcription in vitro. Nucleic Acids Res. 1982 Feb 11;10(3):871–887. doi: 10.1093/nar/10.3.871. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kamen R., Favaloro J., Parker J. Topography of the three late mRNA's of polyoma virus which encode the virion proteins. J Virol. 1980 Feb;33(2):637–651. doi: 10.1128/jvi.33.2.637-651.1980. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kamen R., Favaloro J., Parker J., Treisman R., Lania L., Fried M., Mellor A. Comparison of polyoma virus transcription in productively infected mouse cells and transformed rodent cell lines. Cold Spring Harb Symp Quant Biol. 1980;44(Pt 1):63–75. doi: 10.1101/sqb.1980.044.01.009. [DOI] [PubMed] [Google Scholar]
- Lee D. C., Roeder R. G. Transcription of adenovirus type 2 genes in a cell-free system: apparent heterogeneity of initiation at some promoters. Mol Cell Biol. 1981 Jul;1(7):635–651. doi: 10.1128/mcb.1.7.635. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Legerski R. J., Hodnett J. L., Gray H. B., Jr Extracellular nucleases of pseudomonas BAL 31. III. Use of the double-strand deoxyriboexonuclease activity as the basis of a convenient method for the mapping of fragments of DNA produced by cleavage with restriction enzymes. Nucleic Acids Res. 1978 May;5(5):1445–1464. doi: 10.1093/nar/5.5.1445. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Luse D. S., Haynes J. R., VanLeeuwen D., Schon E. A., Cleary M. L., Shapiro S. G., Lingrel J. B., Roeder R. G. Transcription of the beta-like globin genes and pseudogenes of the goat in a cell-free system. Nucleic Acids Res. 1981 Sep 11;9(17):4339–4354. doi: 10.1093/nar/9.17.4339. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Magnusson G., Berg P. Construction and analysis of viable deletion mutants of polyoma virus. J Virol. 1979 Nov;32(2):523–529. doi: 10.1128/jvi.32.2.523-529.1979. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Manley J. L., Fire A., Cano A., Sharp P. A., Gefter M. L. DNA-dependent transcription of adenovirus genes in a soluble whole-cell extract. Proc Natl Acad Sci U S A. 1980 Jul;77(7):3855–3859. doi: 10.1073/pnas.77.7.3855. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Marinus M. G. Location of DNA methylation genes on the Escherichia coli K-12 genetic map. Mol Gen Genet. 1973 Dec 14;127(1):47–55. doi: 10.1007/BF00267782. [DOI] [PubMed] [Google Scholar]
- Mathis D. J., Chambon P. The SV40 early region TATA box is required for accurate in vitro initiation of transcription. Nature. 1981 Mar 26;290(5804):310–315. doi: 10.1038/290310a0. [DOI] [PubMed] [Google Scholar]
- Maxam A. M., Gilbert W. Sequencing end-labeled DNA with base-specific chemical cleavages. Methods Enzymol. 1980;65(1):499–560. doi: 10.1016/s0076-6879(80)65059-9. [DOI] [PubMed] [Google Scholar]
- McKnight S. L., Gavis E. R., Kingsbury R., Axel R. Analysis of transcriptional regulatory signals of the HSV thymidine kinase gene: identification of an upstream control region. Cell. 1981 Aug;25(2):385–398. doi: 10.1016/0092-8674(81)90057-x. [DOI] [PubMed] [Google Scholar]
- Moreau P., Hen R., Wasylyk B., Everett R., Gaub M. P., Chambon P. The SV40 72 base repair repeat has a striking effect on gene expression both in SV40 and other chimeric recombinants. Nucleic Acids Res. 1981 Nov 25;9(22):6047–6068. doi: 10.1093/nar/9.22.6047. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Myers R. M., Rio D. C., Robbins A. K., Tjian R. SV40 gene expression is modulated by the cooperative binding of T antigen to DNA. Cell. 1981 Aug;25(2):373–384. doi: 10.1016/0092-8674(81)90056-8. [DOI] [PubMed] [Google Scholar]
- Novak U., Dilworth S. M., Griffin B. E. Coding capacity of a 35 percent fragment of the polyoma virus genome is sufficient to initiate and maintain cellular transformation. Proc Natl Acad Sci U S A. 1980 Jun;77(6):3278–3282. doi: 10.1073/pnas.77.6.3278. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Novak U., Griffin B. E. Requirement for the C-terminal region of middle T-antigen in cellular transformation by polyoma virus. Nucleic Acids Res. 1981 May 11;9(9):2055–2073. doi: 10.1093/nar/9.9.2055. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ostrowski M. C., Berard D., Hager G. L. Specific transcriptional initiation in vitro on murine type C retrovirus promoters. Proc Natl Acad Sci U S A. 1981 Jul;78(7):4485–4489. doi: 10.1073/pnas.78.7.4485. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Parker R. C., Watson R. M., Vinograd J. Mapping of closed circular DNAs by cleavage with restriction endonucleases and calibration by agarose gel electrophoresis. Proc Natl Acad Sci U S A. 1977 Mar;74(3):851–855. doi: 10.1073/pnas.74.3.851. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Pribnow D. Nucleotide sequence of an RNA polymerase binding site at an early T7 promoter. Proc Natl Acad Sci U S A. 1975 Mar;72(3):784–788. doi: 10.1073/pnas.72.3.784. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sanger F., Coulson A. R. The use of thin acrylamide gels for DNA sequencing. FEBS Lett. 1978 Mar 1;87(1):107–110. doi: 10.1016/0014-5793(78)80145-8. [DOI] [PubMed] [Google Scholar]
- Sassone-Corsi P., Corden J., Kédinger C., Chambon P. Promotion of specific in vitro transcription by excised "TATA" box sequences inserted in a foreign nucleotide environment. Nucleic Acids Res. 1981 Aug 25;9(16):3941–3958. doi: 10.1093/nar/9.16.3941. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Shenk T. Transcriptional control regions: nucleotide sequence requirements for initiation by RNA polymerase II and III. Curr Top Microbiol Immunol. 1981;93:25–46. doi: 10.1007/978-3-642-68123-3_3. [DOI] [PubMed] [Google Scholar]
- Soeda E., Arrand J. R., Smolar N., Walsh J. E., Griffin B. E. Coding potential and regulatory signals of the polyoma virus genome. Nature. 1980 Jan 31;283(5746):445–453. doi: 10.1038/283445a0. [DOI] [PubMed] [Google Scholar]
- Sollner-Webb B., Reeder R. H. The nucleotide sequence of the initiation and termination sites for ribosomal RNA transcription in X. laevis. Cell. 1979 Oct;18(2):485–499. doi: 10.1016/0092-8674(79)90066-7. [DOI] [PubMed] [Google Scholar]
- Struhl K. Deletion mapping a eukaryotic promoter. Proc Natl Acad Sci U S A. 1981 Jul;78(7):4461–4465. doi: 10.1073/pnas.78.7.4461. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Talkington C. A., Nishioka Y., Leder P. In vitro transcription of normal, mutant, and truncated mouse alpha-globin genes. Proc Natl Acad Sci U S A. 1980 Dec;77(12):7132–7136. doi: 10.1073/pnas.77.12.7132. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Treisman R. Characterisation of polyoma late mRNA leader sequences by molecular cloning and DNA sequence analysis. Nucleic Acids Res. 1980 Nov 11;8(21):4867–4888. doi: 10.1093/nar/8.21.4867. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Treisman R., Cowie A., Favaloro J., Jat P., Kamen R. The structures of the spliced mRNAs encoding polyoma virus early region proteins. J Mol Appl Genet. 1981;1(2):83–92. [PubMed] [Google Scholar]
- Treisman R., Novak U., Favaloro J., Kamen R. Transformation of rat cells by an altered polyoma virus genome expressing only the middle-T protein. Nature. 1981 Aug 13;292(5824):595–600. doi: 10.1038/292595a0. [DOI] [PubMed] [Google Scholar]
- Tsai S. Y., Tsai M. J., O'Malley B. W. Specific 5' flanking sequences are required for faithful initiation of in vitro transcription of the ovalbumin gene. Proc Natl Acad Sci U S A. 1981 Feb;78(2):879–883. doi: 10.1073/pnas.78.2.879. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Tsujimoto Y., Hirose S., Tsuda M., Suzuki Y. Promoter sequence of fibroin gene assigned by in vitro transcription system. Proc Natl Acad Sci U S A. 1981 Aug;78(8):4838–4842. doi: 10.1073/pnas.78.8.4838. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Twigg A. J., Sherratt D. Trans-complementable copy-number mutants of plasmid ColE1. Nature. 1980 Jan 10;283(5743):216–218. doi: 10.1038/283216a0. [DOI] [PubMed] [Google Scholar]
- Tyndall C., La Mantia G., Thacker C. M., Favaloro J., Kamen R. A region of the polyoma virus genome between the replication origin and late protein coding sequences is required in cis for both early gene expression and viral DNA replication. Nucleic Acids Res. 1981 Dec 11;9(23):6231–6250. doi: 10.1093/nar/9.23.6231. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Wasylyk B., Chambon P. A T to A base substitution and small deletions in the conalbumin TATA box drastically decrease specific in vitro transcription. Nucleic Acids Res. 1981 Apr 24;9(8):1813–1824. doi: 10.1093/nar/9.8.1813. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Wasylyk B., Derbyshire R., Guy A., Molko D., Roget A., Téoule R., Chambon P. Specific in vitro transcription of conalbumin gene is drastically decreased by single-point mutation in T-A-T-A box homology sequence. Proc Natl Acad Sci U S A. 1980 Dec;77(12):7024–7028. doi: 10.1073/pnas.77.12.7024. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Wasylyk B., Kédinger C., Corden J., Brison O., Chambon P. Specific in vitro initiation of transcription on conalbumin and ovalbumin genes and comparison with adenovirus-2 early and late genes. Nature. 1980 Jun 5;285(5764):367–373. doi: 10.1038/285367a0. [DOI] [PubMed] [Google Scholar]
- Weaver R. F., Weissmann C. Mapping of RNA by a modification of the Berk-Sharp procedure: the 5' termini of 15 S beta-globin mRNA precursor and mature 10 s beta-globin mRNA have identical map coordinates. Nucleic Acids Res. 1979 Nov 10;7(5):1175–1193. doi: 10.1093/nar/7.5.1175. [DOI] [PMC free article] [PubMed] [Google Scholar]
- de Villiers J., Schaffner W. A small segment of polyoma virus DNA enhances the expression of a cloned beta-globin gene over a distance of 1400 base pairs. Nucleic Acids Res. 1981 Dec 11;9(23):6251–6264. doi: 10.1093/nar/9.23.6251. [DOI] [PMC free article] [PubMed] [Google Scholar]
- van der Eb A. J., Graham F. L. Assay of transforming activity of tumor virus DNA. Methods Enzymol. 1980;65(1):826–839. doi: 10.1016/s0076-6879(80)65077-0. [DOI] [PubMed] [Google Scholar]