Receptors and Entry Cofactors for Retroviruses Include Single and Multiple Transmembrane-Spanning Proteins as well as Newly Described Glycophosphatidylinositol-Anchored and Secreted Proteins

Abstract

SUMMARY In the past few years, many retrovirus receptors, coreceptors, and cofactors have been identified. These molecules are important for some aspects of viral entry, although in some cases it remains to be determined whether they are required for binding or postbinding stages in entry, such as fusion. There are certain common features to the molecules that many retroviruses use to gain entry into the cell. For example, the receptors for most mammalian oncoretroviruses are multiple membrane-spanning transport proteins. However, avian retroviruses use single-pass membrane proteins, and a sheep retrovirus uses a glycosylphosphatidylinositol-anchored molecule as its receptor. For some retroviruses, particularly the lentiviruses, two cell surface molecules are required for efficient entry. More recently, a soluble protein that is required for viral entry has been identified for a feline oncoretrovirus. In this review, we will focus on the various strategies used by mammalian retroviruses to gain entry into the cell. The choice of receptors will also be discussed in light of pressures that drive viral evolution and persistence.

Pseudotyping lentiviral vectors with the wild-type measles virus glycoproteins improves titer and selectivity

“…Owing to their unique property to integrate genetic information into the target cell genome, many viral receptors have been identified using genetic screens based on lentiviral or retroviral vectors. 25 Accordingly, MV WT -HIV vectors may be applied to identify the EpR.…”

Prolonged Adherence of Human Immunodeficiency Virus-Derived Vector Particles to Hematopoietic Target Cells Leads to Secondary Transduction In Vitro and In Vivo

“…Cellular receptors for retrovirus envelope (Env) glycoproteins participate in initial adherence and virus particle uptake (9,25). A wide range of Env glycoproteins are available for pseudotyping of recombinant retrovirus vector particles as a means of restricting species and tissue specificity, thereby allowing cellular targeting (40).…”

Surface-engineering of lentiviral vectors

“…It is anticipated that very few cell-surface molecules may be able to exhibit the particular properties of retroviral receptors, as reflected both by the prominent number of targeted cell-surface molecules that failed to allow retargeted virus entry and by the related topology and function of retroviral receptors for a given family of retroviruses (i.e. multitransmembrane symporters for type C mammalian retroviruses) [109]. More practically, these two central issues have raised serious doubts as far as the ultimate goal of efficient retargeted gene delivery is concerned.…”