However, the amino acid composition of the MSD core does influence the ability of Env to mediate cell-cell fusion and plays a critical role in the infectivity of HIV-1. Replacement of conserved amino acid residues with leucine MM-102 order blocked virus-to-cell fusion and subsequent viral entry into target cells. This restriction could not be released by C-terminal truncation of the gp41 glycoprotein. These studies imply that the highly conserved core residues of the HIV Env MSD, in addition to serving as a membrane anchor, play an important role in mediating membrane fusion during viral entry.”
“Foamy viruses (FVs) are unconventional retroviruses with a replication
strategy that is significantly different from orthoretroviruses and bears some homology to that of hepadnaviruses. Although some cellular proteins, such as APOBEC3, have been reported to block FVs, no restriction by Trim5 alpha has been described to date. The sensitivity of three FV isolates of human-chimpanzee or prototypic (PFV), macaque (SFVmac),
and feline (FFV) origin to a variety of primate Trim5 alpha s was therefore tested. PFV and SFVmac were restricted by Trim5 alpha s from most New World monkeys, but not from other primates, whereas FFV-based vectors were see more restricted by Trim5 alpha s from the great apes gorilla and orangutan. Trim5 alpha s from Old World monkeys did not restrict any FV isolate tested. Capuchin Trim5 alpha was unique, as it restricted SFVmac and FFV but not PFV. Trim5 alpha specificity for FVs was determined by the B30.2 domain, interestingly involving, in some instances, the same residues of the variable regions previously implicated as major determinants ALOX15 for human immunodeficiency virus type 1 restriction. FVs with chimeric Gags were made to map the viral determinants of sensitivity to restriction. The N-terminal half of the Gag molecule was found to contain the regions
that control susceptibility. This region most likely corresponds to the capsid of conventional retroviruses. Due to their unique replication strategy, FVs should provide a valuable new system to examine the mechanism of retroviral restriction by Trim5 alpha.”
“OBJECTIVE: We describe a new strategy to promote axonal regeneration after subacute or chronic spinal cord injury consisting of intramedullary implantation of chitosan guidance channels containing peripheral nerve (PN) grafts.
METHODS: Chitosan channels filled with PN grafts harvested from green fluorescent protein rats were implanted in the cavity 1 week (subacute) or 4 weeks (chronic) after 50-g clip injury at T8 and were compared with similarly injured animals implanted with either unfilled channels or no channels. Functional recovery was measured weekly for 12 weeks by open-field locomotion, after which histological examination was performed.