About MUC-4
The major constituents of mucus, the viscous secretion that covers epithelial surfaces such as those in the trachea, colon, and cervix, are highly glycosylated proteins called mucins. These glycoproteins play important roles in the protection of the epithelial cells and have been implicated in epithelial renewal and differentiation. This gene encodes an integral membrane glycoprotein found on the cell surface, although secreted isoforms may exist. At least two dozen transcript variants of this gene have been found, although for many of them the full-length transcript has not been determined or they are found only in tumor tissues. This gene contains a region in the coding sequence which has a variable number (>100) of 48 nt tandem repeats. [provided by RefSeq, Jul 2008]

About Janelia Fluor 646
Janelia Fluor® 646 was developed at the Janelia Campus of the Howard Hughes Medical Institute but is commercialized by other vendors. The Janelia Fluor®s family is unique in that the fluorophores are cell-permeable and are available in photoactivatable forms. These fluorophores were developed for super-resolution microscopy (STED, PALM and STORM) and live-cell microscopy in the HaloTag and SNAP-tag versions. Janelia Fluor® 646 has an excitation peak at 646 nm and an emission peak at 664 nm.