Fig. 6. CFP-IMP1 does not colocalise with membranous compartments. (A) CFP-IMP1 was cotransfected into NIH 3T3 cells together with YFP-linked markers of the endoplasmic reticulum (YFP-KDEL) and Golgi apparatus (YFP-ß1,4GT), or GFP-IMP1 was cotransfected with a Texas Red-linked marker for acid vesicles. There is no apparent colocalization of fluorescently tagged IMP1 with any of the markers and, in the cases of the Golgi apparatus and acid vesicles, exclusion is often observed. The pictures from cotransfections with ER and Golgi markers are in pseudo-colours to aid visualisation: YFP fluorescence is shown in red, CFP fluorescence is shown in green, and regions of overlap are shown in yellow. (B, upper and middle panels) Western blot with anti-calnexin and anti-IMP1 antibodies of 12 fractions from a 10-60% Nycodenz sedimentation analysis of an undiluted RD cellular lysate. Positions of molecular mass markers are shown at the left. (B, lower panel) Slot-blot analysis of total RNA from the same fractions with a probe specific for IGF-II leader 3 mRNA.