Carbonic Anhydrase III Is Not Required in the Mouse for Normal Growth, Development, and Life Span

Abstract

Carbonic anhydrase III is a cytosolic protein which is particularly abundant in skeletal muscle, adipocytes, and liver. The specific activity of this isozyme is quite low, suggesting that its physiological function is not that of hydrating carbon dioxide. To understand the cellular roles of carbonic anhydrase III, we inactivated the Car3 gene. Mice lacking carbonic anhydrase III were viable and fertile and had normal life spans. Carbonic anhydrase III has also been implicated in the response to oxidative stress. We found that mice lacking the protein had the same response to a hyperoxic challenge as did their wild-type siblings. No anatomic alterations were noted in the mice lacking carbonic anhydrase III. They had normal amounts and distribution of fat, despite the fact that carbonic anhydrase III constitutes about 30% of the soluble protein in adipocytes. We conclude that carbonic anhydrase III is dispensable for mice living under standard laboratory husbandry conditions.

We thank Norman Salem and James Loewke of the Laboratory of Membrane Biochemistry and Biophysics, National Institute on Alcohol Abuse and Alcoholism, for performing the fatty acid analyses. We are grateful to Michael Wilson of the Research Technology Branch, National Institute of Allergy and Infectious Diseases, for guiding the microarray analyses. We thank Hans-Peter Kubis of the Zentrum Physiologie at the Medizinische Hochschule Hannover for the electrophoretic analyses of muscle myosin.