Evidence of a steroidogenic enzyme gene dose effect on adrenal gene expression in hereditary rabbit congenital adrenal hyperplasia.
We previously reported the gene deletion encoding cytochrome P-450 cholesterol side-chain cleavage enzyme (P-450SCC, resulting in complete elimination of the adrenal gene expression and causing congenital adrenal hyperplasia in the rabbit. Using the rabbit congenital adrenal hyperplasia model, we investigated the wild type (wt) P-450SCC gene dose effect on gene expression in three P-450SCC genotype animals [wt/wt, wt/mutant (mt), mt/mt] identified by Southern blot analysis. Northern blots using a rabbit P-450SCC cDNA probe revealed no detectable P-450SCC mRNA in individual adrenals of animals with congenital adrenal hyperplasia (mt/mt) and approximately half or slightly less than half the levels of the mRNA in the pooled adrenals of five heterozygous (wt/mt) newborn animals compared with the mRNA levels in the pooled adrenals of five homozygous normal (wt/wt) newborn animals. Identical P-450SCC mRNA levels were found individual adrenals of adult animals with regard to the P-450SCC genotype, although at a higher expression level than in the newborn animals of the same genotype. Control Northern blots using human CPY21-B cDNA and cytoplasmic actin cDNA probes confirmed the accuracy and integrity of RNA. Western immunoblotting using anti-ovine P-450SCC antibody revealed decreased P-450SCC protein in the adrenals of wt/mt animals at approximately half the level of the P-450SCC protein in the adrenals of the wt/wt animals. Baseline and ACTH-stimulated serum corticosterone (B) levels in vivo were similar between the age-matched wt/mt and wt/wt animals, whereas ACTH-stimulated B levels in adult animals were higher than those in the newborn animals irrespective of P-450SCC genotype.(ABSTRACT TRUNCATED AT 250 WORDS)
Iwamoto
K
K
Department of Pediatrics, University of Illinois College of Medicine, Chicago 60612.
Yang
X
X
Rogerson
F M
FM
Mason
J I
JI
Artwohl
J
J
Bolin
K
K
Klimah
P
P
Swart
P
P
Pang
S
S
D000311:Adrenal Glands / Q000378:metabolism*; D000312:Adrenal Hyperplasia, Congenital / Q000235:genetics* / Q000378:metabolism; D000375:Aging / Q000235:genetics; D000818:Animals; D000831:Animals, Newborn; D002786:Cholesterol Side-Chain Cleavage Enzyme / Q000235:genetics*; D018628:Gene Dosage; D015870:Gene Expression; D005838:Genotype; D006579:Heterozygote; D006720:Homozygote; D010375:Pedigree; D010641:Phenotype; D012333:RNA, Messenger / Q000378:metabolism; D011817:Rabbits; D012016:Reference Values
D012333:RNA, Messenger; D002786:Cholesterol Side-Chain Cleavage Enzyme