This area is very much in my wheelhouse (both the biosynthetic process, and functions of mucins). They’re a pretty interesting biomolecule, present in all animals (slightly different molecules in other branches of life).

It kind of surprises me that such a low fold-change in core1 synthase yields such a huge change in glycocalyx. Everything we know about this enzyme says it is an absolute rocket on substrates, so I can’t really see this process being enzyme-limited. There might be other (mouse specific) things going on here that this is scratching the surface on.