The description of the protein encoded in this ORF: glucose-regulated protein (78 kDa)
The translational frameshift (ribosome slippage) involved: 0
The ribosome read-through involved: no
The alternative forms of this protein occur by the alternative initiation of translation: not tested
The ORF absolute position (the base range includes START and STOP codons or their equivalents): 223-2184
Thoma et al. (2004) did not show activity of BiP IRES in contrast to any other IRES. The negative control
was either BiP IRES in sense orientation on an in vitro run-off transcript without poly(A) tail or BiP IRES
in anti-sense orientation.
The region -93 to -1 does not contain functional 3'-splice acceptor site in the setup used by Baranick et al.
(2008), Supplementary Images 7 and 8. These authors also report no IRES activity of this region as well
in their in vivo based experiments (Figures 1, 2, 3).
We hypothesize that if there is a problematic 3'-splice acceptor site it must be in the region -222 to -94.
Young et al. (2008) tested BiP in a promoter-less construct (Figure 2) and reported a weak promoter. They also
showed that most of the "IRES" activity is related to this cryptic promoter (compare Figure 2B vs. 2C; scale
of 2C higher).
The IRES absolute position (the range includes START and STOP codons or their equivalents): 1-222
How IRES boundaries were determined: experimentally_determined
The sequence of IRES region aligned to its secondary structure (if available):
The BiP IRES was reported by Young et al. (2008) not to be functional in direct RNA transfection (Figure 3).
In Figure 2BC they show that most of the "IRES" activity in NIH3T3 cells is related to the cryptic promoter.