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Biomedical subjects
Publications and source records attributed to Patrick Warren.
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Attempted allelic replacement of 144 Streptococcus pneumoniae open reading frames of previously uncharacterized function led to the identification of 36 genes essential for growth under laboratory conditions. Of these, 14 genes (obg, spoIIIJ2, trmU, yacA, yacM, ydiC, ydiE, yjbN, yneS, yphC, ysxC, ytaG, yloI and yxeH4) were also essential in Staphylococcus aureus and Haemophilus influenzae or Escherichia coli, 2 genes (yrrK and ydiB) were only essential in H. influenzae as well as S. pneumoniae and 8 genes were necessary for growth of S.pneumoniae and S. aureus and did not have a homolog in H. influenzae(murD2, ykqC, ylqF, yqeH, ytgP, yybQ) or were not essential in that organism (yqeL, yhcT). The proteins encoded by these genes could represent good targets for novel antibiotics covering different therapeutic profiles. The putative functions of some of these essential proteins, inferred by bioinformatic analysis, are presented. Four mutants, with deletions of loci not essential for in vitro growth, were found to be severely attenuated in a murine respiratory tract infection model, suggesting that not all targets for antibacterial therapeutics are revealed by simple in vitro essentiality testing. The results of our experiments together with those collated from previously reported studies including Bacillus subtilis, E. coli and Mycoplasma sp. demonstrate that gene conservation amongst bacteria does not necessarily indicate that essentiality in one organism can be extrapolated to others. Moreover, this study demonstrates that different experimental procedures can produce apparently contradictory results.
Suicide gene therapy in combination with pro-drugs represents an attractive approach to the treatment of cancer. Unfortunately this approach is limited by difficulty in targeting all tumor cells, especially those at the distant metastases associated with the most complex tumors. For this reason, attempts to stimulate global anti-tumor immune responses at the sites of effective suicide gene/pro-drug-mediated tumor cell destruction are appealing. Here we show that, by including a gene coding for secreted secondary lymphoid tissue chemokine (SLC) along with the herpes simplex virus thymide kinase (HSV-TK) gene in a bicistronic vector for anti-tumor gene therapy in conjunction with the pro-drug ganciclovir (GCV), we are able to mediate a greatly enhanced anti-tumor effect in the murine B16 melanoma tumor model. The data presented suggests that this enhanced antitumor effect is the result of a strong induced CTL immune response resulting from the recruitment of immune cells to the site of HSV-TK/GCV-induced tumor destruction by the potent chemokine SLC.