Tumor virus A receptor (TVA) (TVA)

The Tumor Virus A (TVA) receptor is a cell-surface protein originally identified in chickens as the primary receptor for subgroup A avian leukosis virus (ALV-A). It is a member of the low-density lipoprotein (LDL) receptor family, characterized by a specific extracellular cysteine-rich repeat that mediates viral envelope binding (Bates et al., 1993). While not naturally occurring in mammals, the TVA receptor is widely utilized in biomedical research through the RCAS/TVA system. This system allows for cell-type-specific gene delivery and the creation of somatic mouse models for various cancers by expressing the TVA receptor under the control of specific promoters (Federspiel et al., 1994). In these models, avian retroviral vectors (RCAS) can selectively infect only the cells expressing the TVA receptor, enabling precise spatial and temporal control of oncogene expression or gene knockdown (Lewis et al., 2003). This technology has been instrumental in studying tumor progression and testing novel therapeutics in a context that closely mimics human disease. Additionally, the human homolog CD320 (transcobalamin receptor) shares structural similarities but does not support ALV-A entry, highlighting the specificity of the TVA-EnvA interaction.

Other names

Avian leukosis virus receptor ATvaALV-A receptorSubgroup A avian leukosis virus receptorChicken vitamin B12 receptor homolog

The TVA receptor facilitates viral entry by binding to the EnvA glycoprotein on the surface of ALV-A or RCAS vectors. This binding event triggers receptor-mediated endocytosis, leading to the fusion of the viral and host cell membranes in a pH-dependent manner, which releases the viral core into the cytoplasm (Bates et al., 1993; Young et al., 1993).