TY - JOUR
T1 - Expression of chicken steroidogenic factor-1 during gonadal sex differentiation
AU - Smith, Craig A.
AU - Smith, Matthijs J.
AU - Sinclair, Andrew H.
PY - 1999/1/1
Y1 - 1999/1/1
N2 - The orphan nuclear receptor, steroidogenic factor-1 (SF1), regulates steroidogenic enzyme expression and is essential for gonadal and adrenal development in mammals. We have examined expression of the chicken homologue, cSF-1, during gonadal sex differentiation using whole mount in situ hybridisation and RNase protection assays (RPA). In the youngest embryos examined (day 3.5; stages 21-22), cSF-1 transcripts were already detectable by in situ hybridisation in the undifferentiated genital ridge of both sexes. Expression continued in the gonads of both sexes at the time of sexual differentiation (days 5.5-6.5; stages 28-30). Expression then became higher in developing ovaries compared to testes at days 6.5-8.5 (stages 30-35). At day 13.5 (stage 40), when the gonads are well differentiated, both ovaries and testes showed cSF-1 expression, with higher levels of expression in the left ovary compared to the right (regressing) gonad in females and compared to testes. RPA analysis of isolated gonads confirmed higher expression of SF- 1 in differentiating ovaries relative to testes. Expression of cSF-1 in the developing adrenal gland was similar for both sexes at all stages examined. In tissue sections of day 8.5 whole mount gonads, cSF-1 expression was localised in the medulla of the ovary and was weakly detectable in the testis. These observations indicate that SF-1 has a conserved role in early gonadal and adrenal development in vertebrates. However, upregulation of cSF- 1 expression during ovarian differentiation is opposite to the pattern seen in mammals, in which SF-1 is down-regulated in females. This difference between the birds and mammals may reflect differences in steroidogenic activity of the embryonic ovary versus the testis in the two groups.
AB - The orphan nuclear receptor, steroidogenic factor-1 (SF1), regulates steroidogenic enzyme expression and is essential for gonadal and adrenal development in mammals. We have examined expression of the chicken homologue, cSF-1, during gonadal sex differentiation using whole mount in situ hybridisation and RNase protection assays (RPA). In the youngest embryos examined (day 3.5; stages 21-22), cSF-1 transcripts were already detectable by in situ hybridisation in the undifferentiated genital ridge of both sexes. Expression continued in the gonads of both sexes at the time of sexual differentiation (days 5.5-6.5; stages 28-30). Expression then became higher in developing ovaries compared to testes at days 6.5-8.5 (stages 30-35). At day 13.5 (stage 40), when the gonads are well differentiated, both ovaries and testes showed cSF-1 expression, with higher levels of expression in the left ovary compared to the right (regressing) gonad in females and compared to testes. RPA analysis of isolated gonads confirmed higher expression of SF- 1 in differentiating ovaries relative to testes. Expression of cSF-1 in the developing adrenal gland was similar for both sexes at all stages examined. In tissue sections of day 8.5 whole mount gonads, cSF-1 expression was localised in the medulla of the ovary and was weakly detectable in the testis. These observations indicate that SF-1 has a conserved role in early gonadal and adrenal development in vertebrates. However, upregulation of cSF- 1 expression during ovarian differentiation is opposite to the pattern seen in mammals, in which SF-1 is down-regulated in females. This difference between the birds and mammals may reflect differences in steroidogenic activity of the embryonic ovary versus the testis in the two groups.
UR - http://www.scopus.com/inward/record.url?scp=0032912639&partnerID=8YFLogxK
U2 - 10.1006/gcen.1998.7214
DO - 10.1006/gcen.1998.7214
M3 - Article
C2 - 10082621
AN - SCOPUS:0032912639
VL - 113
SP - 187
EP - 196
JO - General and Comparative Endocrinology
JF - General and Comparative Endocrinology
SN - 0016-6480
IS - 2
ER -