Regulation of Gene Expression from the Polyoma Late Promoter

Kern, Florian; Delli-Bovi, P; Pellegrini, Sandra; Basilico, Claudio

doi:10.1007/978-1-4613-2087-6_7

Cited by 10 publications

(33 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Plasmids containing base substitution mutations within the Py core ori, 8-142 and 9-40, as previously shown do not replicate in mouse cells (52), as did p48.19 (32). Thus, any alteration of sequences within the Py ori region (plasmids pBE27, pCBYd4, p48.19, 8-142, and 9-40) leads to replication-defective DNA in vivo and in vitro.…”

mentioning

confidence: 71%

See 1 more Smart Citation

DNA sequence requirements for replication of polyomavirus DNA in vivo and in vitro.

Prives¹,

Murakami²,

Kern³

et al. 1987

Mol. Cell. Biol.

View full text Add to dashboard Cite

Cell extracts of FM3A mouse cells replicate polyomavirus (Py) DNA in the presence of immunoaffinitypurified Py large T antigen, deoxynucleoside triphosphates, ATP, and an ATP-generating system. This system was used to examine the effects of mutations within or adjacent to the Py core origin (on) region in vitro. The analysis of plasmid DNAs containing deletions within the early-gene side of the Py core ori indicated that sequences between nucleotides 41 and 57 define the early boundary of Py DNA replication in vitro. This is consistent with previously published studies on the early-region sequence requirements for Py replication in vivo. Deleting portions of the T-antigen high-affinity binding sites A and B (between nucleotides 57 and 146) on the early-gene side of the core on led to increased levels of replication in vitro and to normal levels of replication in vivo. Point mutations within the core ori region that abolish Py DNA replication in vivo also reduced replication in vitro. A mutant with a reversed orientation of the Py core on region replicated in vitro, but to a lesser extent than wild-type Py DNA. Plasmids with deletions on the late-gene side of the core on, within the enhancer region, that either greatly reduced or virtually abolished Py DNA replication in vivo replicated to levels similar to those of wild-type Py DNA plasmids in vitro. Thus, as has been observed with simian virus 40, DNA sequences needed for Py replication in vivo are different from and more stringent than those required in vitro.Replication of polyomavirus (Py) DNA proceeds bidirectionally from a fixed point within the noncoding region of the viral genome (for a review, see reference 16 and references therein). This replication origin (ori) region (Fig. 1) contains multiple T-antigen (T Ag)-binding sites within a G+C-rich 32-base-pair (bp) sequence of dyad symmetry adjacent to a region in which 13 of 14 residues form A * T pairs. It thus bears structural features similar to the replication ori of simian virus 40 (SV40). However, the relationship of the Py ori to other regulatory signals in the noncoding segment is somewhat different from that of SV40. The number and arrangement of large T Ag high-affinity binding sites on the early side of both viral ori regions differ. Also, the relative affinities of Py and SV40 T Ags for binding sites within their respective ori regions are apparently dissimilar (12,14,28,47). Moreover, while both viruses encode enhancer elements, the Py enhancer is almost directly adjacent to the late boundary of the ori region and consists of a series of discrete elements that bear homologies to other enhancer elements including those of SV40, adenovirus Ela, and mouse immunoglobulin genes (2,22,23,26,31,38,46,51,53). By contrast, the SV40 enhancer, a 72-bp repeated sequence (see reference 22 and references therein), is separated from the core ori by a series of G+C-rich sequences (the 21-bp repeats) that form a distinct transcriptional control element to which the cellular transcription factor, Spl, binds (...

show abstract

mentioning

confidence: 71%

“…The replication in permissive cells of many of the mutants used in these studies has been previously described (13,31,32,52). In this study, several of the mutants were either tested for the first time or reexamined for their ability to replicate in WOP mouse cells (13).…”

mentioning

confidence: 99%

DNA sequence requirements for replication of polyomavirus DNA in vivo and in vitro.

Prives¹,

Murakami²,

Kern³

et al. 1987

Mol. Cell. Biol.

View full text Add to dashboard Cite

show abstract

“…More recent data have suggested an additional involvement of middle TAg in regulating the early-late switch by interacting with host signal transduction pathways, which in turn modify transcription factors (10, 12). However, posttranscriptional regulation may play a more important role than large TAg in accumulation of late messages after DNA replication is initiated (3,(13)(14)(15)(16). Activation of polyoma virus late genes is replicationdependent because (i) polyoma mutants carrying temperature-sensitive large TAg mutations cannot proceed into the late phase at a nonpermissive temperature (2); (ii) cytosine arabinoside (araC), a DNA replication inhibitor, prevents the polyoma virus early-late switch (3,14); and (iii) polyoma virus late genes are generally not expressed in significant…”

Section: Introductionmentioning

confidence: 99%

“…Large TAg binds to its target DNA sequences within and adjacent to the replication origin (6)(7)(8) and is required for initiation and maintenance of polyoma virus replication. Previous experiments by others suggest that large TAg also transactivates the late promoter and represses transcriptional activity of early genes (2,(9)(10)(11). More recent data have suggested an additional involvement of middle TAg in regulating the early-late switch by interacting with host signal transduction pathways, which in turn modify transcription factors (10,12).…”

mentioning

confidence: 96%

Polyoma virus early-late switch: regulation of late RNA accumulation by DNA replication.

Liu

Carmichael

1993

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Early in infection of permissive mouse cells, messages from the early region of the polyoma virus genome accumulate preferentially over those from the late region. After initiation of DNA replication, the balance between early and late gene expression is reversed in favor of the late products. In previous work from our laboratory, we showed that viral early proteins do not activate the polyoma late promoter in the absence ofDNA replication. Here The molecular details underlying the early-late switch are poorly understood, although large TAg is known to play a pivotal role. Large TAg binds to its target DNA sequences within and adjacent to the replication origin (6-8) and is required for initiation and maintenance of polyoma virus replication. Previous experiments by others suggest that large TAg also transactivates the late promoter and represses transcriptional activity of early genes (2, 9-11). More recent data have suggested an additional involvement of middle TAg in regulating the early-late switch by interacting with host signal transduction pathways, which in turn modify transcription factors (10, 12). However, posttranscriptional regulation may play a more important role than large TAg in accumulation of late messages after DNA replication is initiated (3,(13)(14)(15)(16). Activation of polyoma virus late genes is replicationdependent because (i) polyoma mutants carrying temperature-sensitive large TAg mutations cannot proceed into the late phase at a nonpermissive temperature (2); (ii) cytosine arabinoside (araC), a DNA replication inhibitor, prevents the polyoma virus early-late switch (3,14); and (iii) polyoma virus late genes are generally not expressed in significantThe publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact. levels in transformed nonpermissive cells, in which polyoma fails to replicate (15). Regulation of gene expression by DNA replication could be achieved via trans-or cis-acting mechanisms. Trans-acting factors may be modified, induced, or titrated as a result ofDNA replication. Alternatively, changes in chromatin structure induced by replication may exert a direct cis effect on late gene expression (17, 18). In simian virus 40 (SV40), late genes can be activated in trans by large TAg in the absence of DNA replication (19)(20)(21)(22). Recently, a trans effect involving depletion of an important transcriptional factor has been suggested for polyoma virus late gene activation (12). In contrast, previous reports presented evidence for a direct effect of the SV40 replication origin in activating the SV40 late promoter (23). Results from adenoviruses (24, 25) indicated cis-acting template effects on transcriptional control and posttranscriptional processing. A systematic study of a cis effect of DNA replication on polyoma late gene activation has not yet been reported.We show here that TAg expression in the absence of DNA replic...

show abstract

“…(ii) An enhancer region, originally defined as the 244 bp between the BcII (bp 5021) and PvuII (bp 5264) restriction enzyme sites (17,81), has been subdivided into two unrelated but functionally redundant elements, enhancer A and enhancer B, both of which are capable of stimulating transcription of heterologous genes in an orientation-and position-independent manner (42). Studies with gel retention and nuclease mapping assays have identified several cellular protein factors that bind specifically to the B enhancer (7,26,70 (9,38) and in vivo (2,32,40) and that at least some of the elements of the polyomavirus early promoter, including portions of the enhancer, may regulate the levels of transcription from the late promoter of that virus (8,13,(52)(53)(54).…”

mentioning

confidence: 99%

Enhancer and promoter elements from simian virus 40 and polyomavirus can substitute for an upstream activation sequence in Saccharomyces cerevisiae.

1990

View full text Add to dashboard Cite

Ten fragments of higher eucaryotic DNA were tested for upstream activation sequence activity in Saccharomyces cerevisiae by inserting them upstream of a CYCI::lacZ promoter lacking an upstream activation sequence. Fragments containing the 21-base-pair repeat region, the enhancer of simian virus 40 or both strongly stimulated I8-galactosidase synthesis, and three fragments from the polyomavirus enhancer region stimulated moderate levels. Three of the four controls of random DNA sequences failed to stimulate significant levels, and the fourth stimulated moderate levels. The stimulation in all cases was independent of the orientation of the inserted fragment. Two series of clones were examined in which between one and six tandemly arranged copies of a fragment were inserted into the Xhol site of the vector. Very interestingly, we detected an apparent exponential relationship between the number of copies of a fragment and the amount of 0-galactosidase produced. Southern analysis showed that increases in enzyme activity were not a result of increased plasmid copy number. Rather, quantitative S1 nuclease analysis demonstrated that the increases were correlated with steady-state levels of lacZ-specific mRNA. We suggest that there may be an evolutionary relationship between some transcriptional activation sequences in yeast cells and the higher eucaryotic regulatory elements that we tested.The promoter elements that regulate transcription by RNA polymerase II in both yeast cells and higher eucaryotes have been intensively studied. In yeast cells, transcription units (reviewed in reference 79) contain one or more of the following elements: (i) initiator elements, which are located at the RNA initiation site; (ii) TATA regions, which are located about 40 to 120 base pairs (bp) upstream of the specificity start site and govern the rate of RNA initiation; and (iii) upstream activation sequences (UASs), which lie further upstream and activate transcription in response to nutritional or physiological signals (reviewed in reference 34). UASs, when isolated and linked to heterologous genes, are active in both orientations and can function at distances up to 600 bp upstream of the RNA initiation site, but not when placed downstream of it (35,45,78). In three wellcharacterized systems (GAL4 [10,29,30,49,50,66], GCN4 [1,11,14,44,47,80], and HAP1 [67-69]), genetic and biochemical analysis has shown that UASs are DNA-binding sites for transcriptional regulatory proteins.The promoters of the DNA tumor viruses simian virus 40 (SV40) and polyomavirus can serve as prototypes of higher eucaryotic promoters. Each of these viruses contains two major transcription units, for early and late mRNAs, which initiate in a region near the origin of DNA replication and extend in opposite directions around the circular genome (see Fig. 2 for a diagram of the regulatory regions of both viruses).At early times after SV40 infection, the synthesis of the major viral mRNA species is regulated by the early-early promoter, which consists of at least three ...

show abstract

Regulation of Gene Expression from the Polyoma Late Promoter

Cited by 10 publications

References 38 publications

DNA sequence requirements for replication of polyomavirus DNA in vivo and in vitro.

DNA sequence requirements for replication of polyomavirus DNA in vivo and in vitro.

Polyoma virus early-late switch: regulation of late RNA accumulation by DNA replication.

Enhancer and promoter elements from simian virus 40 and polyomavirus can substitute for an upstream activation sequence in Saccharomyces cerevisiae.

Contact Info

Product

Resources

About