Effects of the MITF
isoforms A and M are comparable. A
: Full-length (FL)
MITF isoforms A and M and their known domains are shown with the
corresponding amino acids: MITF-A domains A
, common domains bHLH-LZ
and the MITF-M specific N-terminal region (M
six amino acids of the M isoform (aa187–192) are shown. B
Interactions of the full-length OTX2 and domains from the MITF
isoform A (FL: aa1–520; A-B1b-AD: aa1–297) or M (FL: aa1–419;
M-AD: aa1–196) were measured and are shown with gray columns.
The level of MITF auto-activation is indicated by white columns.
Assays were performed as in Figure 7
independent experiments each performed in quadruplicate. C
ARPE-19 cells were cotransfected with the proximal TYR
promoter lacking any OTX2 sites but with intact (−152: black
columns) or mutated MITF binding sites (−152mMmE: gray columns).
Normalized luciferase activities are relative to TYR
promoter construct −152 (=1) cotransfected with the empty
expression vector pCR3 (=no TF). Data are means±SEM from two
independent transfections each performed in triplicate.