The description of the protein encoded in this ORF: Mus musculus hypoxia inducible factor 1, alpha subunit (Hif1a).
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: no
The ORF absolute position (the base range includes START and STOP codons or their equivalents): 258-2768
Transiently transfected cells with pRF based vector. Integrity of the bicistronic transcripts verified by
RNase protection assay and Northern blot (Lang et al., 2002).
Bert et al. (2006) tested Hif1a IRES in HeLa cells using promoter-less plasmids with or without the enhancer
left in (Figure 2). They showed there is a cryptic promoter activatable when the enhancer is left in.
Also Young et al. (2008) report in Figure 2 a cryptic promoter in NIH3T3 cells.
The IRES absolute position (the range includes START and STOP codons or their equivalents): 1-257
How IRES boundaries were determined: guessed
The sequence of IRES region aligned to its secondary structure (if available):
This mRNA remains bound to polysomes both in normoxia and hypoxia. Exact IRES region was not determined.
Values represent length of the 5' UTR.
Bert et al. (2006) reported that despite the contribution of the cryptic promoter in in vivo-based
assays Hif1a IRES has "some" activity.
Young et al. (2008 reported that Hif1a IRES is not functional in directly transfected RNAs (Figure 3) nor in
NIH3T3 cells transfected by a plasmid encoding a bicistronic mRNA when subtracted the IRES-like activity
contributed by the promoter (Figure 2B vs. 2C).