Cloning of a fragment of the osteonectin gene from goldfish, Carassius auratus: its expression and potential regulation by estrogen.
During reproduction, female teleost fish display increased plasma estrogen and greatly increased total plasma calcium concentrations; the main source of this calcium seems to be the scale. Osteonectin, a collagen-binding glycoprotein, is a major noncollagenous constituent of mammalian bone and is a product mainly of the osteoblasts. RT-PCT has been applied to clone and sequence part of the osteonectin gene from the goldfish, Carassius auratus. The use of a goldfish scale cell line (GFS) and a specific probe to goldfish osteonectin mRNA has allowed the study of the potential effects of estrogen and other calcitropic hormones on the cells derived from the scales. Osteonectin mRNA was detected in teleost bone, scale, and GFS cells by Northern blot analysis, hybridising to a transcript of approximately 1.6 kb. Expression of osteonectin mRNA was markedly down-regulated by 17beta-estradiol (10(-8) to 10(-11) M) in a dose-dependent fashion but was unaffected by calcitriol, TGFbeta, IL-1beta, calcitonin, and PTHrP. Down-regulation of osteonectin by estrogen is further evidence that estrogen participates in calcium homeostasis during vitellogenesis, acting directly on the cells responsible for matrix and mineral fluxes in scales.
Lehane
D B
DB
Human Metabolism and Clinical Biochemistry, University of Sheffield Medical School, Sheffield, S10 2RX, UK.
McKie
N
N
Russell
R G
RG
Henderson
I W
IW
D000595:Amino Acid Sequence; D000818:Animals; D015152:Blotting, Northern / Q000662:veterinary; D001842:Bone and Bones / Q000737:chemistry; D002117:Calcitriol / Q000494:pharmacology; D002417:Cattle; D002645:Chickens; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000737:chemistry; D004958:Estradiol / Q000494:pharmacology; D004967:Estrogens / Q000502:physiology*; D005260:Female; D005786:Gene Expression Regulation; D006054:Goldfish / Q000235:genetics* / Q000502:physiology; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology; D008969:Molecular Sequence Data; D015676:Osteonectin / Q000235:genetics*; D044162:Parathyroid Hormone-Related Protein; D016133:Polymerase Chain Reaction / Q000662:veterinary; D011506:Proteins / Q000494:pharmacology; D016212:Transforming Growth Factor beta / Q000494:pharmacology; D014982:Xenopus laevis
D018076:DNA, Complementary; D004967:Estrogens; D007375:Interleukin-1; D015676:Osteonectin; C470121:PTHLH protein, human; D044162:Parathyroid Hormone-Related Protein; D011506:Proteins; D016212:Transforming Growth Factor beta; D004958:Estradiol; D002117:Calcitriol