Antibody:	4G6
Detection system:	Secondary antibody coupled to fluorescein

Structure	Level	Pattern	Image	Note
TS21: submandibular gland primordium epithelium	Present	Widespread	1A	Expressed throughout basement membranes of both the epithelial clusters and the stalk.
TS21: submandibular gland primordium mesenchyme	Absent		1A	No expression in capillary basement membranes or in the mesenchyme.

Structure	Level	Pattern	Image	Note
TS27: submandibular duct	Present	Regionally restricted	1B	Expressed in the basement membranes of interlobular and intralobular ducts. Weak staining in basement membranes of some acini.
TS27: submandibular gland	Present	Regionally restricted	1B	Expressed in the basement membranes of interlobular and intralobular ducts. Weak staining in basement membranes of some acini. Expressed in interlobular arteries, but not veins.

Structure	Level	Pattern	Image	Note
TS28: submandibular duct	Present	Regionally restricted	1C	Expressed in basement membranes of inter- and intralobular excretory ducts, and of the granular convoluted tubules.
TS28: submandibular gland	Present	Regionally restricted	1C	Expressed in basement membranes of inter- and intralobular excretory ducts, and of the granular convoluted tubules. Scattered staining in the myoepithelium (spindle- or crescent-shaped structures). Expressed in the walls of small arteries and nerves.