Expression of a human cytomegalovirus latency-associated homolog of interleukin-10 during the productive phase of infection

Abstract

The human cytomegalovirus UL111A region is active during both productive and latent phases of infection. During productive infection, the virus expresses ORF79, a protein with oncogenic properties, and cmvIL-10, a functional homolog of human IL-10. During latent infection of myeloid progenitor cells, an alternately spliced variant of cmvIL-10, termed latency-associated (LA) cmvIL-10 has previously been identified. To determine whether LAcmvIL-10 transcription occurs during productive infection, we performed 5' and 3' RACE to map UL111A-region transcripts in productively infected human foreskin fibroblasts (HFFs). This analysis revealed the presence of a singly spliced UL111A-region transcript predicted to encode LAcmvIL-10. This transcript was expressed in HFFs with early (beta) kinetics, a temporal class that differs from that of ORF79 (alpha kinetics) and cmvIL-10 (gamma kinetics). These data identify and map a transcript encoding a latency-associated homolog of IL-10 which is expressed by the virus during the productive phase of infection.

Immunomodulatory Properties of a Viral Homolog of Human Interleukin-10 Expressed by Human Cytomegalovirus during the Latent Phase of Infection

“…A similar transcript, which appears to initiate from a slightly different site, but which is predicted to also encode LAcmvIL-10, has also been detected during productive infection of human foreskin fibroblasts (HFFs) (20). Thus, the LAcmvIL-10 open reading frame (ORF) appears to be latency associated rather than latency specific.…”

“…It was concluded that recombinant LAcmvIL-10 was successfully expressed by and purified from E. coli. For production of mammalian cell-expressed proteins, LAcmvIL-10 and cmvIL-10 cDNAs were cloned, and recombinant proteins were expressed in HEK293 cells as previously described (20). A mock control consisting of HEK293 cells transfected ϩ GM-Ps treated with either bacterial cell-expressed and purified LAcmvIL-10 and cmvIL-10 (C and D) or conditioned medium (CM) from mammalian cells transfected with LAcmvIL-10 and cmvIL-10 expression vectors (E and F).…”

Latent human cytomegalovirus enhances HIV-1 infection in CD34+ progenitor cells

“…To determine the state of HCMV infection in PB-CD34 cells, we examined if HCMV latencyassociated genes are expressed, including UL111.5A, LUNA, and UL138. 3,5,6 qPCR was performed on PB-CD34 cells infected with mock, HCMV strain Towne, or the clinical isolate Merlin for 5 days ( Figure 1C). Consistent with previous findings, we found that both HCMV strains express UL111.5A and LUNA significantly in PB-CD34 cells.…”

“…These latencyassociated genes include UL111.5A, LUNA, and UL138 and can regulate host cell responses, such as downregulating major histocompatibility complex (MHC) class II molecules, while inducing host interleukin-10 (IL-10), chemokine (C-C motif) ligand 8 (CCL8), and the multidrug resistance-associated protein-1 (MRP1). [3][4][5][6][7][8] These HCMV latent genes are important for facilitating establishment/maintenance of latency in which host cell mechanisms are modulated. However, only few latent genes have known functions.…”

CD8+ T-cell recognition of human cytomegalovirus latency-associated determinant pUL138

“…The mechanistic roles of these transcripts are not fully understood. Their expression is not restricted to latent infection; most are also expressed at some point during productive infection (Jenkins et al, 2008;Lunetta & Wiedeman, 2000). Whilst UL138 has been demonstrated to be an important component of latent infection, it is likely that other viral transcripts also contribute to latent infection (Goodrum et al, 2007;Petrucelli et al, 2009).…”