Rhesus Macaque TRIM5 Alleles Have Divergent Antiretroviral Specificities

Abstract

TRIM5␣ is a potent barrier to cross-species retroviral transmission, and TRIM5␣s from different species have divergent antiretroviral specificities. Multiple TRIM5 alleles circulate within rhesus macaque populations. Here we show that they too have different antiretroviral specificities, highlighting how TRIM5 genotypes contribute to protection in an individual or a population.TRIM5␣ is an important mediator of antiretroviral innate immunity in mammals and represents a significant barrier to zoonotic transmission. It blocks retroviral infection in a species-specific manner; for example, human immunodeficiency virus type 1 (HIV-1) is restricted by Old World monkey TRIM5␣ but is not significantly restricted by human TRIM5␣ (12,26,31). TRIM5␣ consists of RING, B-box 2, and coiledcoil domains (RBCC), comprising a tripartite motif, as well as a C-terminal B30.2 domain, which determines antiviral specificity, and appears to interact directly with the incoming viral capsid (27). Recently, multiple TRIM5 alleles have been identified in an Old World monkey, the rhesus macaque (Macaca mulatta) (17). These alleles have surprisingly divergent B30.2 domains and are maintained at high frequencies in macaque populations. Because variation in the sequence of the B30.2 domain can have such profound effects on the antiretroviral specificity of TRIM5␣, these divergent macaque B30.2 domains have likely been selected to interact with different viral capsids. Remarkably, one of the TRIM5 alleles, Mamu-7, encodes a TRIM5-cyclophilin A (CypA) fusion protein with a different spectrum of antiretroviral activity to TRIM5␣ (4, 13, 18, 29, 30). In Mamu-7/TRIMCyp, exon 6 is joined to a downstream CypA cDNA sequence, leaving a vestigial B30.2 domain in the genome (Fig. 1A). Here we demonstrate the differential restriction of HIV-2 by rhesus TRIM5 alleles and map the determinant of restriction to a polymorphism in the B30.2 V1 region. Furthermore, we show that the different TRIM5 alleles have dominant negative properties against each other when exogenously expressed.To further characterize the degree of polymorphism in rhesus macaques, we sequenced TRIM5 exon 8 from DNA purified from 31 Indian and 38 Chinese Macaca mulatta monkeys from the Biomedical Primate Research Centre breeding colony in Rijswijk, The Netherlands (30). We identified the TRIM5 alleles 30). Predicted B30.2 domain amino acid sequences are shown in Fig. 1B. We also identified a mutation, G402D, in one animal. We are unsure whether this represents a mutation or a genuine polymorphism but have included it in our analyses. In order to explore the antiretroviral specificities of the various B30.2 domains, we generated a murine leukemia virus (MLV)-based vector (32) that expresses TRIM5␣ Mamu-1, driven by an internal cytomegalovirus promoter, with a silent SalI site at the V-301 and D-302 codons, facilitating the insertion of the entire exon 8 sequences from at this site. We then transduced CRFK cells with vectors encoding the different B30.2 domains appended to the hemagglutinin...

Structural insight into HIV-1 capsid recognition by rhesus TRIM5α

“…S4), even though the L4/5 region of HIV CA is much longer than the corresponding region in MLV CA. An emerging consensus is that a conserved TRIM5α-binding mode exists for various viral capsids and that the surface details of the CA lattice dictate the species-specific interaction with TRIM5α (5,14,22,(41)(42)(43). On the other hand, TRIM5α possesses an intriguing curvature-independent pattern-recognition property.…”

Molecular evolution of the antiretroviral TRIM5 gene

“…For example, a six nucleotide insertion/deletion polymorphism in the V1 region of rhesus macaque TRIM5α (TFP339Q in Fig. 5) is sufficient to explain differential restriction of HIV-2 (Wilson et al 2008a) and SIVagmTAN (Newman and Johnson, unpub-lished results) by the most common rhTRIM5α alleles, but it is not clear whether this is due to the small difference in length or amino acid composition (or both). Similarly, a 20 amino acid duplication found in an African green monkey TRIM5α ortholog transfers the capacity to restrict SIVmac239 when reconstituted in the context of human TRIM5α (Nakayama et al 2005).…”

Recent Insights into the Mechanism and Consequences of TRIM5α Retroviral Restriction

“…A number of independent studies have examined polymorphisms in rhesus macaques and identified alleles that exhibit significant differences in their ability to restrict diverse retroviruses. [75][76][77][78] One of these studies, by Lim and colleagues, observed significant differences in the ability of different TRIM5a alleles present in these macaques to inhibit infection by SIVmac239, a viral strain commonly used to infect rhesus macaques to induce an AIDS-like disease in studies of AIDS pathogenesis and vaccine strategies. [79][80][81] Critically, not only did intraspecies allelic differences affect restriction of SIVmac239 in single cycle infectivity assays, these differences also conferred altered susceptibility to critical aspects of AIDS-like disease progression, including peak and set-point plasma RNA levels, CD4 T cell depletion, and survival.…”

“…In humans, the majority of polymorphisms occur within the RBCC motif in regions of the protein that are not thought to be responsible for modulating TRIM5a specificity to individual retroviruses. [70][71][72]74 Conversely, almost all of the nonsynonymous SNPs identified in rhesus macaques are located in the SPRY and CC domains, [75][76][77][78] which are the regions of the protein reported to dictate the specificity of TRIM5a restriction (Fig. 2).…”