Skip to main content
. 2011 Oct 1;15(7):1957–1997. doi: 10.1089/ars.2010.3586

FIG. 9.

FIG. 9.

Incorporation of Sec at UGA codons. The recognition of the UGA (opal) codon as a site for incorporation of Sec rather than a stop codon involves many specialized factors, such as SBP2, which binds to the stem-loop or Sec incorporation sequence (SECIS) element in the 3′ UTR of the GPx-1 transcript. SBP2 recruits the specific Sec tRNA and the Sec elongation factor (eEFsec) that are necessary for insertion of Sec at the ribosomes. Other factors, such as ribosomal L30, NSEP1, and nucleolin, may also bind to the SECIS element to modulate incorporation (28, 99). In the absence of selenium, eIF4a3 competes for SBP2 binding, essentially inhibiting GPx-1 transcription (not shown in figure). UAG (amber) stop codon specifies translational termination of GPx-1.