Artificial mutations and natural variations in the CD46 molecules from human and monkey cells define regions important for measles virus binding

Abstract

CD46 was previously shown to be a primate-specific receptor for the Edmonston strain of measles virus. This receptor consists of four short consensus regions (SCR1 to SCR4) which normally function in complement regulation. Measles virus has recently been shown to interact with SCR1 and SCR2. In this study, receptors on different types of monkey erythrocytes were employed as "natural mutant proteins" to further define the virus binding regions of CD46. Erythrocytes from African green monkeys and rhesus macaques hemagglutinate in the presence of measles virus, while baboon erythrocytes were the least efficient of the Old World monkey cells used in these assays. Subsequent studies demonstrated that the SCR2 domain of baboon CD46 contained an Arg-to-Gln mutation at amino acid position 103 which accounted for reduced hemagglutination activity. Surprisingly, none of the New World monkey erythrocytes hemagglutinated in the presence of virus. Sequencing of cDNAs derived from the lymphocytes of these New World monkeys and analysis of their erythrocytes with SCR1-specific polyclonal antibodies indicated that the SCR1 domain was deleted in these cells. Additional experiments, which used 35 different site-specific mutations inserted into CD46, were performed to complement the preceding studies. The effects of these artificial mutations were documented with a convenient binding assay using insect cells expressing the measles virus hemagglutinin. Mutations which mimicked the change found in baboon CD46 or another which deleted the SCR2 glycosylation site reduced binding substantially. Another mutation which altered GluArg to AlaAla at positions 58 and 59, totally abolished binding. Finally, the epitopes for two monoclonal antibodies which inhibit measles virus attachment were mapped to the same regions implicated by mutagenesis.

Molecular Determinants of Species Specificity in the Coronavirus Receptor Aminopeptidase N (CD13): Influence of N-Linked Glycosylation

“…The glycosylation of the cellular receptor impacts virus receptor interactions of measles, HIV, and murine leukemia viruses (MuLVs) (17,45,59). Studies of the measles virus receptor (CD46) demonstrate that N-glycan addition increases receptor activity (26,(43)(44)(45). In contrast, removal of two N-linked glycosylation sites in CXCR4, an HIV coreceptor, increases fusion and entry of HIV type 2 strain ROD/B, illustrating that glycosylation of virus receptors may weaken their interaction with viral attachment proteins (59).…”

“…It is possible that these two regions of APN that are separated by more than 400 amino acids are close together in the three-dimensional structure of APN, and evidence of FIPV receptor function by an hAPN-pAPN (AP33) chimera suggests that it is likely (33). Additionally, it is possible that the N-linked glycosylation site that blocks receptor activity for HCoV-229E may enhance TGEV receptor function as is true for measles virus and CD46 (26,43,44). However, none of the hAPN constructs with mutations from amino acids 288 to 295 showed any receptor activity for TGEV.…”

Morbillivirus Receptors and Tropism: Multiple Pathways for Infection

“…Previous studies have located the MeV binding site on CD46 to the SCR1 and SCR2 domains of the receptor (Buchholz et al, 1997;Hsu et al, 1997;Casasnovas et al, 1999;Christiansen et al, 2000; Figure 2). Functional studies in vitro have suggested that signaling via CD46 is an important component of MeV pathogenesis.…”

Adenovirus vectors in hematopoietic stem cell genome editing

“…Of all mammals, only NHPs express CD46 in a pattern similar to humans [83]. The only notable difference is that human erythrocytes lack CD46, while it is expressed on erythrocytes from NHPs.…”