Activity of the human immunodeficiency virus type 1 cell cycle-dependent internal ribosomal entry site is modulated by IRES trans-acting factors. - Vallejos M; Deforges J; Plank TD; Letelier A; Ramdohr P; Abraham CG; Valiente-Echeverría F; Kieft JS; Sargueil B; López-Lastra M (Nucleic acids research, 2011)