Ks. Wang et al., 3 SUBSETS OF GENES WHOSE TISSUE-SPECIFIC EXPRESSION IS SEX AND AGE-DEPENDENT CAN BE IDENTIFIED WITHIN THE RAT ALPHA(2U)-GLOBULIN FAMILY, Developmental genetics, 21(3), 1997, pp. 234-244
The rat alpha(2v)-globulins are encoded by a multigene family whose 20
-25 members are subjected to multihormonal regulation that is dependen
t upon the sex of the animal, the developmental stage and the tissue b
eing examined. Using RT-PCR and diagnostic restriction analysis of the
products, we have examined the specificity of the expression of diffe
rent members of the gene family. All family members can be classified
into three subsets, depending on how the amplified cDNA responds io di
gestion with ApaLl, Sstl and Vspl. Subset A contains the restriction s
ites for both ApaLl and SsA but not Vspl and typifies the genes expres
sed in the salivary glands of both mature and juvenile animals of both
sexes, where ii is the only subset expressed. This subset of genes al
so accounts for all the transcripts observed in the kidneys and mammar
y glands of juvenile males. Although subset A was represented in the t
ranscript populations of all the other tissues examined, iis proportio
n relative to the total varied greatly. The two other subsets were sub
set V, which contains only the restriction site for Vspl, and subset N
, which lacks all three restriction sites. in all the other tissues ex
amined, two or all three of the subsets were expressed, usually in a m
anner that was unique to the sex and age of the tissue in question. Th
e proportion of each of the three alpha(2v)-globulin subsets in the al
pha(2v)-globulin gene family was determined by quantitation of the res
triction products of amplified genomic DNA. interestingly, the most pr
evalent subset in the genome (N) has the most limited tissue expressio
n pattern, but is found in liver and preputial glands, the tissues exp
ressing the most substantial quantities of alpha(2v)-globulin. These r
esults indicate the complexity of the regulation of the alpha(2v)-glob
ulins and point io the necessity for gene specific analyses if the exp
ression of the family is to be understood in molecular terms. (C) 1997
Wiley-Liss, Inc.