title: Identification of essential cis element in 5'UTR of Nef mRNA for Nef translation.
abstract: Nef is one of the accessory proteins of the human immunodeficiency virus type 1 (HIV-1). Nef is translated from multiple-spliced mRNAs transcribed from the viral genome, whose mRNAs have a relatively long 5' untranslated region (5'UTR). Here, we identified a cis element in the 5'UTR of Nef mRNA essential for efficient Nef translation, which was named the Nef-translation essential region (NER). Mutants with a deleted NER in the 5'UTR of the HIV-1 NL4-3 strain showed an almost undetectable Nef expression owing to a low Nef translation efficiency. The NER of the NL4-3 strain was predicted to form putative stem loops. Although the 5'UTR showed significant but relatively low internal ribosome entry site (IRES) activity, the mechanism of 5'cap-dependent translation mainly contributed to the Nef translation from its Nef mRNA. Altogether, it was clarified that not only the 5' cap but also the NER in the 5'UTR is an essential cis element for efficient Nef translation, which is not a typical 5'-cap-dependent mechanism, and that there must be an as yet unknown mechanism using the NER for efficient Nef translation.
authors: Minami
authors: M
authors: Yamamoto
authors: Keisuke
authors: K
authors: Harada
authors: Shozo
authors: S
authors: Shoji
authors: Shogo
authors: S
authors: Misumi
authors: Department of Pharmaceutical Biochemistry, Faculty of Life Sciences, Kumamoto University, 5-1 Oe- Honmachi, Chuo-ku, Kumamoto 862-0973, Japan. tkmnnbtk@gpo.kumamoto-u.ac.jp.
authors: Nobutoki
authors: N
authors: Takamune
mesh_terms: D020121:5' Untranslated Regions; D004252:DNA Mutational Analysis; D015967:Gene Expression Regulation, Viral; D015497:HIV-1 / Q000235:genetics / Q000502:physiology*; D006801:Humans; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000235:genetics*; D054311:nef Gene Products, Human Immunodeficiency Virus / Q000096:biosynthesis* / Q000235:genetics*
chemical_list: D020121:5' Untranslated Regions; D012333:RNA, Messenger; D054311:nef Gene Products, Human Immunodeficiency Virus; C514837:nef protein, Human immunodeficiency virus 1