Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

ABSTRACT Adenovirus Death Protein (ADP) expression during late stages of a lytic infection releases mature virions to promote viral spread, thus leading to death of the host cell. We sought to investigate ADP expression patterns in persistently infected human lymphocytes cells. We hypothesized that low expression of ADP allows the virus to persist while high expression would promote lytic infection in lymphocytes. Accordingly, we found ADP expressed in low amount in BJAB and KE37 cells, while lytically infected Jurkat cells demonstrated higher ADP expression in both protein and transcript levels. ADP overexpression in persistently infected lymphocytes did not alter the viability of these cells, or their level of ADP expression. In contrast, Jurkat cells infected with an ADP-deleted virus had increased survival and maintained viral DNA for greater than 1-month, suggesting conversion to a persistent infection. Also manipulating ADP expression had minimal impact on the total virus yield from infected lymphocytes.

The activity of Adenosine diphosphoribosyl transferase (ADPRT), the chromatin-bound enzyme which specifically catalyses the cleavage of oxidized NAD⁺ with the concomitant covalent attachment of the ADP-ribose moiety to acceptor proteins, was investigated in Polyoma Virus-Transformed (PyY) and Untransformed BHK21/C13 (BHK) cells. It was shown that ADPRT activity was consistently 2-4 fold higher in PyY cells than in BHK cells. The spectrum of (ADP-ribose)_n residues synthesised by the two cell types was very similar when analysed by hydroxyapatite column chromatography. Poly (ADP-ribose) Glycohydrolase activity in the two cell types was identical with 25-30% degradation of the poly(ADP-ribose) over a period of 90 minutes. DNA damage resulting from incubation with Deoxyribonuclease was reflected by an immediate increase in ADPRT activity and an increase in (ADP-ribose)_n chain length by both cell types. Polyamines which are present at high concentrations in rapidly dividing tissues were able to stimulate ADPRT activity both <i>in vitro</i> and <i>in vivo</i> in BHK and PyY cells. In general the average chain length of ADP-ribose residues synthesised remained unaltered. No significant increase in the level of DNA-strand breakage could be detected in the polyamine-treated cells. Depletion of the cellular polyamine levels resulted in stimulation of ADPRT activity, but there was no significant difference in the spectrum of (ADP-ribose)_n residues synthesised. Again no significant increase in the level of DNA-strand breaks could be detected in the polyamine-depleted cells. These results suggest that DNA-damage may not be the only means of regulating ADPRT activity and that polyamines may have a role to play in this regard <i>in vivo</i>.

ABSTRACT Adenovirus Death Protein (ADP) expression during late stages of a lytic infection releases mature virions to promote viral spread, thus leading to death of the host cell. We sought to investigate ADP expression patterns in persistently infected human lymphocytes cells. We hypothesized that low expression of ADP allows the virus to persist while high expression would promote lytic infection in lymphocytes. Accordingly, we found ADP expressed in low amount in BJAB and KE37 cells, while lytically infected Jurkat cells demonstrated higher ADP expression in both protein and transcript levels. ADP overexpression in persistently infected lymphocytes did not alter the viability of these cells, or their level of ADP expression. In contrast, Jurkat cells infected with an ADP-deleted virus had increased survival and maintained viral DNA for greater than 1-month, suggesting conversion to a persistent infection. Also manipulating ADP expression had minimal impact on the total virus yield from infected lymphocytes.

Thesis (Ph.D. in Microbiology) -- University of Colorado Denver, 2007. / Typescript. Includes bibliographical references (leaves 183-207). Free to UCD affiliates. Online version available via ProQuest Digital Dissertations;

Freiburg (Breisgau), Universiẗat, Diss., 2005.

Thèse (M.Sc.)--Université Laval, 2003. / Bibliogr.: f. 77-93. Publié aussi en version électronique.

No description available.

A method for the high resolution fractionation of ADP-ribose polymers has been developed that allows isolation of highly purified polymers of defined size and branching fequency. The key features of the method are purification using dihydroxyboronyl-BioRex 70 and fractionation by anion exchange HPLC.

In this study, ADP-ribosylation reactions in the murine myelomonocytic cell line WEHI-3BD+ were investigated.