Molecular cloning and developmental expression of corticotropin-releasing factor in the chicken.
We have characterized the structure of the chicken corticotropin-releasing factor (CRF) gene through cDNA cloning and genomic sequence analysis, and we analyzed the expression of CRF mRNA and peptide in the diencephalon of the chick throughout embryonic development. The structure of the chicken CRF gene is similar to other vertebrate CRF genes and contains two exons and a single intron. The primary structure of the mature chicken CRF peptide is identical to human and rat CRF. This is the first archosaurian CRF gene to be characterized. We used RIAs to analyze CRF peptide content in the diencephalon and the median eminence and plasma corticosterone during the last week of embryonic development. We also developed a semiquantitative RT-PCR method to analyze the expression of CRF mRNA during the same period. CRF peptide content in the diencephalon increased, whereas peptide content in the ME decreased just before hatching, suggesting that release and biosynthesis are coupled. Plasma corticosterone concentration significantly increased between embryonic d 20 and the first day post hatch. By contrast, CRF mRNA levels in the diencephalon decreased just before hatching. Changes in CRF production just before hatching may be causally related to the regulation of the thyroid and interrenal axes at this stage of chicken development.
Vandenborne
Kristien
K
Laboratory of Comparative Endocrinology, Zoological Institute, Katholieke Universiteit Leuven, B-3000 Leuven, Belgium.
De Groef
Bert
B
Geelissen
Sofie M E
SM
Boorse
Graham C
GC
Denver
Robert J
RJ
Kühn
Eduard R
ER
Darras
Veerle M
VM
Van der Geyten
Serge
S
D000375:Aging / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism; D001483:Base Sequence; D002642:Chick Embryo / Q000378:metabolism / Q000502:physiology; D002645:Chickens / Q000097:blood / Q000235:genetics* / Q000254:growth & development; D003001:Cloning, Molecular; D003345:Corticosterone / Q000097:blood; D003346:Corticotropin-Releasing Hormone / Q000235:genetics* / Q000378:metabolism; D004027:Diencephalon / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D008473:Median Eminence / Q000378:metabolism; D008969:Molecular Sequence Data; D015394:Molecular Structure; D011333:Pro-Opiomelanocortin / Q000235:genetics; D045706:Proprotein Convertase 2 / Q000235:genetics; D011498:Protein Precursors / Q000235:genetics; D012333:RNA, Messenger / Q000378:metabolism
D011498:Protein Precursors; D012333:RNA, Messenger; D011333:Pro-Opiomelanocortin; D003346:Corticotropin-Releasing Hormone; D045706:Proprotein Convertase 2; D003345:Corticosterone