murine leukemia virus spreading in mice impaired in the biogenesis of secretory lysosomes and ca2+-regulated exocytosis小鼠白血病病毒的传播在小鼠受损分泌溶酶体的生物起源和ca2 +调节胞外分泌.pdfVIP

Murine Leukemia Virus Spreading in Mice Impaired in the Biogenesis of Secretory Lysosomes and Ca2+- Regulated Exocytosis 1 1¤ 1 2 2 Wai-Tsing Chan , Nathan M. Sherer , Pradeep D. Uchil , Edward K. Novak , Richard T. Swank , Walther Mothes1* 1 Section of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, United States of America, 2 Department of Molecular and Cellular Biology, Roswell Park Cancer Institute, Buffalo, New York, United States of America Abstract Background: Retroviruses have been observed to bud intracellularly into multivesicular bodies (MVB), in addition to the plasma membrane. Release from MVB is thought to occur by Ca2+-regulated fusion with the plasma membrane. Principal Findings: To address the role of the MVB pathway in replication of the murine leukemia virus (MLV) we took advantage of mouse models for the Hermansky-Pudlak syndrome (HPS) and Griscelli syndrome. In humans, these disorders are characterized by hypopigmentation and immunological alterations that are caused by defects in the biogenesis and trafficking of MVBs and other lysosome related organelles. Neonatal mice for these disease models lacking functional AP-3, Rab27A and BLOC factors were infected with Moloney MLV and the spread of virus into bone marrow, spleen and thymus was monitored. We found a moderate reduction in MLV infection levels in most mutant mice, which differed by less than two-fold compared to wild-type mice. In vitro, MLV release form bone-marrow derived macrophages was slightly enhanced. Finally, we found no evidence for a Ca2+-regulated release pathway in vitro. Furthermore, MLV replication was only moderately affected in mice lacking Synaptotagmin VII, a C