Mapping Shroom3 expression across the adult mouse

Shroom3 is an actin binding protein integral to apical constriction and apical-basal elongation during mammalian morphogenesis. Shroom3 function has been demonstrated in the development of the heart, neural tube, gut tube, eye, thyroid bud, and kidneys, with mutations linked to human congenital defects including anencephaly, spina bifida, cleft lip and palate, and ventricular septal defects. Genome-wide association studies implicate Shroom3 in human conditions such as chronic kidney disease and heterotaxy. While this suggests that Shroom3 expression continues postnatally, the extent of adult expression patterns remain unexplored. To address this, we first harvested organs from adult mice heterozygous for a LacZ reporter inserted into the Shroom3 allele (Shroom3^+/Gt). Organs were stained in wholemount with X-gal and cleared in glycerol to identify which tissues expressed Shroom3 and to localize the expression within the tissue. Wildtype organs were then harvested and fluorescently stained to localize Shroom3 protein in tissue sub-structures. From this, we have characterized previously unknown Shroom3 expression in many adult organs including the bladder and reproductive systems, as well as established postnatal Shroom3 expression in organs thought to only have developmental expression including the eye and whisker pad. Our results also demonstrate organs which did not show Shroom3 expression, including the liver and pancreas. This data suggests that Shroom3 has roles in a wider number of tissues than previously thought and provides a foundation for future hypotheses regarding the biological and pathological significance of Shroom3.