RESEARCH Balanced splicing at the T t

ep type 1 (HIV-1) into the host genome, the cellular RNA ximity to the 5 ′ end of unspliced RNAs to be the first Erkelenz et al. Retrovirology (2015) 12:29 DOI 10.1186/s12977-015-0154-8distal reading frames to CAP-proximal ones efficiently translated by the scanning ribosome. Düsseldorf, Germany Full list of author information is available at the end of the articlepolymerase II (RNAPII) transcribes just one primary RNA from the 5′-long terminal repeat (5′-LTR). This pre-mRNA preserves the open reading frames (ORFs) for all of 18 different viral proteins altogether driving replication, infectivity and immune evasion [1-5]. CAP-ones efficiently recognized by the scanning 43S riboso-mal subunit. However, expression of seven other CAP-distal ORFs including Tat and Rev is indispensable for efficient viral replication. That is why a substantial amount of the primary RNA – approximately half – is diverted into the splicing pathway. Alternative splice site selection allows the excision of upstream sequences con-taining translational inhibitory AUGs and converts CAP-* Correspondence