Developmental expression, cellular localization, and testosterone regulation of alpha 1-antitrypsin in Mus caroli kidney.

J J Latimer,F G Berger,H Baumann

doi:10.1016/s0021-9258(18)45254-4

Abstract

alpha 1-Antitrypsin (alpha 1-protease inhibitor), an essential plasma protein, is synthesized predominantly in the liver of all mammals. We have previously shown that Mus caroli, a Southeast Asian mouse species is exceptional in that it expresses abundantly alpha 1-antitrypsin mRNA and polypeptide, in the kidney as well as the liver (Berger, F.G., and Baumann, H. (1985) J. Biol. Chem. 260, 1160-1165) providing a unique model for examination of the evolution of genetic determinants of tissue-specific gene expression. In the present paper, we have further characterized alpha 1-antitrypsin expression in M. caroli. The extrahepatic expression of alpha 1-antitrypsin is limited to the kidney, specifically within a subset of the proximal tubule cells. The developmental pattern of alpha 1-antitrypsin mRNA expression in the kidney differs from that in the liver. In the kidney, alpha 1-antitrypsin mRNA is present at only 2-4% adult level at birth and increases very rapidly to adult level during puberty between 26 and 36 days of age. There are no significant changes in liver alpha 1-antitrypsin mRNA levels during this period. Testosterone, while having only modest affects on alpha 1-antitrypsin mRNA accumulation in the adult kidney, causes a 20-fold induction of the mRNA in the pre-pubertal kidney. This suggests that the increase in alpha 1-antitrypsin mRNA expression during puberty is testosterone mediated. Southern blot analyses of Mus domesticus and M. caroli genomic DNA and a cloned M. caroli alpha 1-antitrypsin genomic sequence, indicate that a single alpha 1-antitrypsin gene exists in M. caroli, whereas multiple copies exist in M. domesticus. These data show that the alteration in tissue specificity of alpha 1-antitrypsin mRNA accumulation that has occurred during Mus evolution is associated with distinctive developmental and hormonally regulated expression patterns.

Highlights

RESULTSTissue Specificity of al-Antitrypsin Expression in M. caroli-In order to determine the sitesof al-antitrypsin mRNA expressionin M. caroli, total RNAfrom 11 male M. caroli organs was examined by Northern analysis (Fig. 1).Hybridizationwas performedwithanal-antitrypsincRNAprobe which greatly increasedthe sensitivityof the analysisr,elative to conventional cDNA probes
We havepreviously demonstratedthatthe wild derived olmCeifxvhRtaeeiNmsrmsAi(u.nBe2aa-e6tsnir0podg,enepc1rioo,1ffliF6yc.t0phgG-eee1p.n1,eteia6vdn5oeedl),xuippBtnirroaoethunvsesmiodikofaiinnngd.gInenn,naeHeyutt.hnic(eia1qsd9upee8wrt5eemesr)llmoJedn.aietnsBlaitfpnohoalter.spert4mm,i0soR0suu0NseeAmssRppaeNetcciAnfieiocscri,omtMypaiu(el5ss/l)cec.evaWlerlol)hs,liil,iieetnxMathlhs.iobecaietlrxsiovplaeirernpsrs(uoaednpsuupctsrheuoesaxliammla-Rlaa-tNnaetnlAiyttirit2ynr0py0tsph0isne-in we have further characterized a,antitrypsin expres- kidney, at levels ranging from 2000 to 6000 copies/cell
Tissue Specificity of al-Antitrypsin Expression in M. caroli-In order to determine the sitesof al-antitrypsin mRNA expressionin M. caroli, total RNAfrom 11 male M. caroli organs was examined by Northern analysis (Fig. 1).Hybridizationwas performedwithanal-antitrypsincRNAprobe which greatly increasedthe sensitivityof the analysisr,elative to conventional cDNA probes

Summary

RESULTS

Tissue Specificity of al-Antitrypsin Expression in M. caroli-In order to determine the sitesof al-antitrypsin mRNA expressionin M. caroli, total RNAfrom 11 male M. caroli organs was examined by Northern analysis (Fig. 1).Hybridizationwas performedwithanal-antitrypsincRNAprobe which greatly increasedthe sensitivityof the analysisr,elative to conventional cDNA probes. RNA was prepared from the organsof adult M. caroli males, fractionated by agarose gel electrophoresis (15 pg of RNAllane except for liver and kidney), blotted onto nitrocellulose, and hybridized to "Plabeled al-antitrypsin cRNA. In M. caroli kidney, intense Northern blot analysis of liver RNA from M. caroli males hybridization was present in the tubulecells primarily in the a t various ages Of the area of strongest hybridization within the kidney sug- caroli al-antitrypsin mRNAlevels are only 33% of C57BL/6J gests that a,-antitrypsin transcription occurs in a subset of adult male levels. Since the tubule cells which hybridized with the a,- Females undergo a developmental increase in the kidney antitrypsin cRNA probe represent approximately20-30% of a,-antitrypsin mRNA levels similar to that seen in males.

Days Postpartum

Southern blot analyses of restriction endonuclease digests of

MUP days

DISCUSSION