Expression of transforming growth factor-alpha and epidermal growth factor receptor in human fetal kidneys.
Beginning at the fifth week of fetal life, successive generations of individual nephrons are induced by contact between metanephric mesenchyme and ureteric bud. Following phenotypic transformation, cells of each primitive renal vesicle undergo a phase of rapid cell division. In order to identify genes which might regulate nephron development in man, we screened adult and fetal kidney RNA for expression of a panel of growth-related genes. Among the genes which were expressed at higher levels in fetal kidney was the epidermal growth factor (EGF) receptor. There is controversy as to the most likely physiologic EGF receptor ligand in fetal kidney; we were able to identify a transcript for transforming growth factor-alpha (TGF-alpha) but not EGF on Northern blots of fetal kidney RNA. Since the abundance of TGF-alpha mRNA is low, we confirmed its presence by polymerase chain reaction amplification. Using specific radioimmunoassays, we also provide direct evidence for TGF-alpha but not EGF peptide in extracts of fetal kidney and mid-gestational amniotic fluid. We suggest that TGF-alpha/EGF receptor interactions may serve an important function in development of human fetal kidney.
Goodyer
P R
PR
Department of Pediatrics, McGill University-Montreal Children's Hospital Research Institute, Quebec, Canada.
Fata
J
J
Mulligan
L
L
Fischer
D
D
Fagan
R
R
Guyda
H J
HJ
Goodyer
C G
CG
D001483:Base Sequence; D015152:Blotting, Northern; D015139:Blotting, Southern; D004247:DNA; D015342:DNA Probes; D066246:ErbB Receptors / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D006801:Humans; D007668:Kidney / Q000196:embryology / Q000378:metabolism*; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012313:RNA / Q000378:metabolism; D016211:Transforming Growth Factor alpha / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism
D015342:DNA Probes; D016211:Transforming Growth Factor alpha; D012313:RNA; D004247:DNA; D066246:ErbB Receptors