In 786-O cells, we recovered a transcript lacking exons
13 to 15, using 3′ rapid amplification of cDNA ends, in
keeping with the MLPA data (Supplementary Fig. S3; data
not shown) and with Western blot data indicating that
these cells produce a HIF1α variant that reacts with a polyclonal
antibody, but not a C-terminal monoclonal antibody
(Fig. 2A). This transcript is predicted to encode a fusion protein,
as it contains several in-frame exons from a neighboring
gene (data not shown). For unclear reasons, however, this
transcript greatly exceeds the apparent molecular weight of
the mRNA detected in these cells by Northern blot analysis
(Fig. 2B)