Regardless of the absence of gag and pol, the HIV-LTR promoter is fully functional to support the expression of other HIV genes (e.g. nef, env, vpr) and hence proteins in the HIV-Tg26 mice and cause several lesions, including skin papillomata, cataracts and CKD (Putatunda et al., 2018; Kopp et al., 1993; Cheung et al., 2015). Here, ERVW-1 is linked to cataract.