The most recently discovered carbonic anhydrase, CA XV, is expressed in the thick ascending limb of Henle and in the collecting ducts of mouse kidney.
BACKGROUND
Carbonic anhydrases (CAs) are key enzymes for physiological pH regulation, including the process of urine acidification. Previous studies have identified seven cytosolic or membrane-bound CA isozymes in the kidney. Recently, we showed by in situ hybridization that the mRNA for the most novel CA isozyme, CA XV, is present in the renal cortex. CA XV is a unique isozyme among mammalian CAs, because it has become a pseudogene in primates even though expressed in several other species.


RESULTS
In the present study, we raised a polyclonal antibody against recombinant mouse CA XV that was produced in a baculovirus/insect cell expression system, and the antibody was used for immunohistochemical analysis in different mouse tissues. Positive immunoreactions were found only in the kidney, where the enzyme showed a very limited distribution pattern. Parallel immunostaining experiments with several other anti-CA sera indicated that CA XV is mainly expressed in the thick ascending limb of Henle and collecting ducts, and the reactions were most prominent in the cortex and outer medulla.


CONCLUSIONS
Although other studies have proposed a role for CA XV in cell proliferation, its tightly limited distribution may point to a specialized function in the regulation of acid-base homeostasis.
Institute of Medical Technology, University of Tampere, Tampere, Finland.
Sina
S
Saari
Mika
M
Hilvo
Peiwen
P
Pan
Gerolf
G
Gros
Nina
N
Hanke
Abdul
A
Waheed
William S
WS
Sly
Seppo
S
Parkkila
D000818:Animals; D002256:Carbonic Anhydrases / Q000096:biosynthesis* / Q000502:physiology; D049109:Cell Proliferation; D003600:Cytosol / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D006706:Homeostasis; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D007685:Kidney Tubules, Collecting / Q000378:metabolism*; D008138:Loop of Henle / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D020033:Protein Isoforms; D011544:Pseudogenes
D020033:Protein Isoforms; D002256:Carbonic Anhydrases; C507974:carbonic anhydrase XV, mouse