Expression of functional nerve growth factor receptors in pancreatic beta-cell lines and fetal rat islets in primary culture.
Previous data demonstrated that one rat insulinoma cell line, RINm5F cells, which is a rat beta-cell line derived from a pancreatic tumor, express mRNA coding for both the low- and the high-affinity nerve growth factor receptors. Goals of this study were to extend our data to other beta-cell lines and fetal islets in primary culture and to study further the binding characteristics of nerve growth factor receptors on beta-cells. Northern blot analysis revealed that not only a panel of endocrine beta-cell lines (RINm5F, INS-1, beta-TC3) but also fetal rat islets in primary culture express mRNA coding for trk-A, which has been proposed to be the neuronal high-affinity nerve growth factor receptors. Reverse polymerase chain reaction followed by sequencing revealed that the sequence of trk-A receptor in RINm5F cells is identical to that of trk-A expressed in PC12 cells. The expression of the low-affinity nerve growth factor receptor was examined by Northern blot analysis that showed low-affinity nerve growth factor receptor to be expressed in RINm5F and INS-1 cell lines, in fetal rat islets in primary culture, but not in beta-TC3-cells. Binding experiments revealed the presence of low- and high-affinity nerve growth factor binding sites, identical to those described for PC12 cells, on RINm5F and INS-1 cells and only high-affinity binding sites on beta-TC3 cells. Exposure of all three beta-cell lines to nerve growth factor increased NGFI-A and c-fos mRNA steady-state levels, showing that these receptors are functional.(ABSTRACT TRUNCATED AT 250 WORDS)
Scharfmann
R
R
INSERM U120, Hôpital R. Debre, Paris, France.
Tazi
A
A
Polak
M
M
Kanaka
C
C
Czernichow
P
P
D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D002478:Cells, Cultured; D017931:DNA Primers; D005333:Fetus; D015870:Gene Expression; D016762:Genes, fos; D007340:Insulinoma; D007515:Islets of Langerhans / Q000378:metabolism*; D007700:Kinetics; D008969:Molecular Sequence Data; D009414:Nerve Growth Factors / Q000378:metabolism; D016716:PC12 Cells; D010190:Pancreatic Neoplasms; D016133:Polymerase Chain Reaction; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis* / Q000378:metabolism; D016760:Proto-Oncogene Proteins c-fos / Q000096:biosynthesis; D012333:RNA, Messenger / Q000096:biosynthesis / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D020794:Receptor Protein-Tyrosine Kinases / Q000096:biosynthesis* / Q000378:metabolism; D020917:Receptor, trkA; D017475:Receptors, Nerve Growth Factor / Q000096:biosynthesis* / Q000378:metabolism
D017931:DNA Primers; D009414:Nerve Growth Factors; D011518:Proto-Oncogene Proteins; D016760:Proto-Oncogene Proteins c-fos; D012333:RNA, Messenger; D017475:Receptors, Nerve Growth Factor; D020794:Receptor Protein-Tyrosine Kinases; D020917:Receptor, trkA