title: A Nascent Peptide Signal Responsive to Endogenous Levels of Polyamines Acts to Stimulate Regulatory Frameshifting on Antizyme mRNA.
abstract: The protein antizyme is a negative regulator of cellular polyamine concentrations from yeast to mammals. Synthesis of functional antizyme requires programmed +1 ribosomal frameshifting at the 3' end of the first of two partially overlapping ORFs. The frameshift is the sensor and effector in an autoregulatory circuit. Except for Saccharomyces cerevisiae antizyme mRNA, the frameshift site alone only supports low levels of frameshifting. The high levels usually observed depend on the presence of cis-acting stimulatory elements located 5' and 3' of the frameshift site. Antizyme genes from different evolutionary branches have evolved different stimulatory elements. Prior and new multiple alignments of fungal antizyme mRNA sequences from the Agaricomycetes class of Basidiomycota show a distinct pattern of conservation 5' of the frameshift site consistent with a function at the amino acid level. As shown here when tested in Schizosaccharomyces pombe and mammalian HEK293T cells, the 5' part of this conserved sequence acts at the nascent peptide level to stimulate the frameshifting, without involving stalling detectable by toe-printing. However, the peptide is only part of the signal. The 3' part of the stimulator functions largely independently and acts at least mostly at the nucleotide level. When polyamine levels were varied, the stimulatory effect was seen to be especially responsive in the endogenous polyamine concentration range, and this effect may be more general. A conserved RNA secondary structure 3' of the frameshift site has weaker stimulatory and polyamine sensitizing effects on frameshifting.
authors.affiliation: School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland.
authors.forename: Martina M
authors.initials: MM
authors.lastname: Yordanova
authors.affiliation: Department of Biology, Texas A&M University, College Station, Texas 77843-3258.
authors.forename: Cheng
authors.initials: C
authors.lastname: Wu
authors.affiliation: Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119991, Russia.
authors.forename: Dmitry E
authors.initials: DE
authors.lastname: Andreev
authors.affiliation: Department of Biology, Texas A&M University, College Station, Texas 77843-3258.
authors.forename: Matthew S
authors.initials: MS
authors.lastname: Sachs
authors.affiliation: School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland; Department of Human Genetics, University of Utah, Salt Lake City, Utah 84112-5330. Electronic address: j.atkins@ucc.ie.
authors.forename: John F
authors.initials: JF
authors.lastname: Atkins
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001487:Basidiomycota / Q000737:chemistry / Q000235:genetics*; D015317:Biogenic Polyamines / Q000378:metabolism*; D018965:Frameshifting, Ribosomal; D005656:Fungal Proteins / Q000235:genetics*; D057809:HEK293 Cells; D006801:Humans; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D021382:Protein Sorting Signals; D012333:RNA, Messenger / Q000737:chemistry / Q000235:genetics*; D012568:Schizosaccharomyces / Q000737:chemistry / Q000235:genetics
chemical_list: D015317:Biogenic Polyamines; D005656:Fungal Proteins; D021382:Protein Sorting Signals; D012333:RNA, Messenger
keywords: ORF; RNA structure; antizyme; frameshifting; mRNA; polyamine; ribosome; translation regulation