Download or read book Organization and Function of Simian Virus 40 Origin Region Sequences in Late Gene Transcription and Replication written by Shih Sung Gong and published by . This book was released on 1987 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Comparison of the DNA Sequences of Simian Virus 40 Required for the Synthesis of Early RNA and Viral DNA written by Gerald Zachary Hertz and published by . This book was released on 1986 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Characterization of Simian Virus 40 Late Leader Region Mutants written by Alice Barkan and published by . This book was released on 1983 with total page 516 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Cellular Factors Regulating Transcription of the Simian Virus 40 Major Late Promoter written by Steven Robert Wiley and published by . This book was released on 1993 with total page 524 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Simian Virus 40 Large Tumor Antigen written by Robin Clark and published by . This book was released on 1986 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Regulation of Simian Virus 40 Transcription written by Donald Charles Rio and published by . This book was released on 1983 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Initiation of Simian Virus 40 SV40 DNA Replication written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: It is well established that during initiation of SV40 DNA synthesis, a double hexamer of T antigen forms over the origin and acts as a bidirectional helicase. The subsequent events are much less clear. In fact, the structure on which DNA synthesis begins is not known, but has been hypothesized to be the double hexamer tightly associated with cellular initiation factors replication protein A (RPA), topoisomerase I (topo I) and more loosely with DNA polymerase & alpha;/primase (pol/prim). I now demonstrate that after a double hexamer forms over small origin fragments, a new structure consisting of a single hexamer associated with DNA is generated in an ATP dependent reaction from double hexamers. This structure, called the preinitiation complex (PIC), requires about 5 minutes to form whereas double hexamers are generated within 20 seconds. Importantly, PICs can associate with RPA and topo I whereas double hexamers, which have not been converted to PICs, can only bind to topo I. PICs are not simply T antigen hexamers associated with single-stranded DNA as the latter structures were shown not to bind RPA or topo I. Topo I can bind to an RPA-associated PIC, but RPA cannot bind to a topo I-associated PIC suggesting that the binding order is RPA then topo I. Importantly, DNA synthesis activity appears to be associated with the PICs but not with double hexamers. In this dissertation, a series of mutants with single-point substitutions in the helicase domain are generated to discover activities required for initiation of DNA replication. Four of these mutants (456 RA, 460ED, 462GA, and 499DA) are normal in their ability to hydrolyze ATP and are capable of associating into double hexamers in the presence of origin DNA. Furthermore, they possess normal ability to bind to single-stranded DNA. However, they fail to melt the early palindrome region of the origin. They also are severely impaired in unwinding origin-containing DNA fragments and in carrying out a helicase reaction with an M13 partial duplex DNA substrate. Interestingly, these mutants retain some ability to perform a helicase reaction with artificial replication forks, indicating that their intrinsic helicase activity is functional. Intriguingly, these mutants have almost completely lost their ability to bind to double-stranded DNA nonspecifically. Taken together, my data indicate that structural distortion and subsequent unwinding of the origin depend upon T antigen's ability to bind to DNA nonspecifically.
Download or read book Simian Virus 40 DNA Replication written by Stephen Todd Smale and published by . This book was released on 1986 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Synthesis and Function of Simian Virus 40 Late RNA Species written by Peter Joseph Good and published by . This book was released on 1987 with total page 568 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mutational Analysis of the Origin Binding Domain of Simian Virus 40 Large T antigen Provides Insights Into Its Function in DNA Unwinding written by Erin C. Foster and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: DNA replication is an essential process of cell division required in order to maintain genomic integrity of all dividing cells. Although advancements have been made toward further understanding of this process, much is still unknown about the mechanisms underlying DNA replication, especially in mammalian systems. Eukaryotic DNA replication is a tightly regulated and complex process involving a myriad of proteins and numerous origins. Due to this complexity Simian Virus 40 (SV40) is used as a model system to simplify the investigation of the function of individual protein components. The replication of SV40 DNA employs one multifunctional viral protein, large T-antigen (T-ag). Many structural and genetic studies have provided a wealth of information about T-ag; however much remains unknown about the specific interactions between T-ag, DNA and replication factors and the precise sequence of events during replication. SV40 large T-ag is a multidomain protein that functions in origin recognition and unwinding events during initiation of SV40 DNA replication. The Origin Binding Domain (OBD) of T-ag plays a critical role during initiation to position T-ag on the origin through the use of a DNA binding motif consisting of A1 and B2 loops. After origin recognition, T-ag forms a double hexamer over the origin. Within each hexamer, the OBD adopts a lock washer structure where the origin recognizing A1 and B2 loops face towards the helicase domain and likely become unavailable for DNA binding. New surfaces of the OBD monomers are positioned along the DNA axis during hexamer formation. The role of the central channel of the OBD hexamer in DNA replication was investigated by analyzing the effects of mutations of residues lining the channel. All mutants showed binding defects with origin DNA and ssDNA especially at low protein concentrations, but only half were defective at supporting DNA replication in vitro. All mutants were normal in unwinding linear origin DNA fragments. However, replication defective mutants failed to unwind a small origin containing circular DNA whereas replication competent mutants did so normally. The presence of RPA and/or pol/prim restored circular DNA unwinding activity of compromised mutants probably by interacting with the separated DNA strands on the T-ag surface. The addition of RPA also recovered the ability of replication deficient mutants to support initiation and complete DNA replication in vitro. The addition of pol/prim resulted in the greatest recovery of mutant activity in minicircle unwinding and initiation. Compared to other polymerases tested, pol/prim was the only polymerase able to rescue mutant activity to WT levels indicated that this stimulation is specific to pol/prim. Of the four subunits of the pol/prim complex that could be responsible for stimulating mutant activity, the p180 subunit appeared to be active in recovering circular DNA unwinding. These results indicated a role for the OBD central channel in binding and threading ssDNA during unwinding of circular SV40 DNA. Mixing mutant and WT T-ag in minicircle unwinding assays suggested that only one monomer in an OBD hexamer was necessary for DNA unwinding. Results allowed for the development of a model of DNA threading through the T-ag complex illustrating how single stranded DNA could pass close to a trough generated by key residues in one monomer of the OBD hexamer.
Download or read book SV40 Protocols written by Leda Raptis and published by Humana Press. This book was released on 2013-08-14 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt: Simian virus 40 gained notoriety in the 1960s because it was found to be a contaminant of polio and adenovirus vaccines that had been administered to millions of healthy individuals worldwide. The public health implications of this revelation provided the initial impetus for an in-depth study of SV40 biology. Later work showed that SV40 DNA sequences as well as infectious virus are in fact found in human tumors and may have contributed to oncog- esis. It also turned out that SV40 uses mostly cellular machinery to carry out many steps in viral infection, which makes it a powerful probe for examining many fundamental questions in eukaryotic molecular biology. SV40 Pro- cols consolidates a number of well-tested step-by-step techniques in one v- ume; experts with hands-on experience in particular methods give detailed accounts of their optimized experimental protocols, so that the beginner, as well as more experienced researchers, may readily overcome problems of ambiguity often present in the literature. As with other DNA tumor viruses, the response of cultured cells to SV40 infection depends upon the species being infected. Monkey cells s- port virus production, which leads to their death, whereas rodent cells p- duce only the early proteins and acquire a transformed phenotype. Thus, SV40 Protocols is organized in two sections. The first relates to assays of the lytic cycle of the virus, and the second deals with transformation.
Download or read book A Structure function Analysis of Simian Virus 40 Major Capsid Protein Vp1 written by Peggy Pei-Wen Li and published by . This book was released on 2001 with total page 394 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Human Herpesviruses written by Ann Arvin and published by Cambridge University Press. This book was released on 2007-08-16 with total page 1325 pages. Available in PDF, EPUB and Kindle. Book excerpt: This comprehensive account of the human herpesviruses provides an encyclopedic overview of their basic virology and clinical manifestations. This group of viruses includes human simplex type 1 and 2, Epstein–Barr virus, Kaposi's Sarcoma-associated herpesvirus, cytomegalovirus, HHV6A, 6B and 7, and varicella-zoster virus. The viral diseases and cancers they cause are significant and often recurrent. Their prevalence in the developed world accounts for a major burden of disease, and as a result there is a great deal of research into the pathophysiology of infection and immunobiology. Another important area covered within this volume concerns antiviral therapy and the development of vaccines. All these aspects are covered in depth, both scientifically and in terms of clinical guidelines for patient care. The text is illustrated generously throughout and is fully referenced to the latest research and developments.
Download or read book DNA Tumor Viruses written by Blossom Damania and published by Springer Science & Business Media. This book was released on 2008-12-19 with total page 805 pages. Available in PDF, EPUB and Kindle. Book excerpt: This unique book focuses on the DNA viruses in the human population that are associated with cancers. It covers most of the viruses that are thought to contribute to human malignancy. This book represents a comprehensive review of the field of DNA tumor virology. Right now, while there are books out there that cover individual viruses that are also covered in this book, there is no single book that covers this topic comprehensively. This book is the first current, comprehensive review of its kind in the market.
Download or read book Regulations of Late Region Gene Expression of Simian Virus 40 written by Stephen Warren Hartzell and published by . This book was released on 1985 with total page 398 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Functional Significance of the Simian Virus 40 Late MRNA Polyadenylation Signal RNA Secondary Structure written by Holly Hans Henry and published by . This book was released on 2000 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Translation of the Late MRNAs of Simian Virus 40 written by Sylvia Ann Sedman and published by . This book was released on 1989 with total page 380 pages. Available in PDF, EPUB and Kindle. Book excerpt:
