Identification of pro-EPIL and EPIL peptides translated from insulin-like 4 (INSL4) mRNA in human placenta.
Recently, a new member of the insulin gene superfamily termed insulin-like 4 (INSL4) was identified in the human placenta and uterus. The present study investigated whether placenta translates INSL4 mRNA into a putative peptide named early placenta insulin-like (EPIL). Among antibodies elicited against the C chain of pro-EPIL, one antibody (AB7381) was specifically directed against the C chain 59-88 portion, and among those elicited against the A and B chains of EPIL, one antibody (Ab1661) was directed against the A chain 115-139 and the B chain 23-52 portions. Immunohistochemistry based on antibody 7381 to pro-EPIL and antibody 1661 to EPIL demonstrated that the cytotrophoblast from early placenta preferentially expresses the pro-EPIL peptide, whereas the EPIL peptide is expressed by both the cytotrophoblast and the syncytiotrophoblast. At term, the pro-EPIL peptide was detected in villous cytotrophoblast cells, whereas the EPIL peptide was not detected. Moreover, in vitro experiments performed on term placenta showed that the steady state levels of INLS-4 mRNA in the cytotrophoblast are 10 times (one log unit) lower than in the differentiated villous syncytiotrophoblast cells. Taken together, these findings reveal that expression of EPIL peptides in the villous cytotrophoblast is different from that displayed by the syncytiotrophoblast. Finally, these data are the first demonstration that INSL4 mRNA are translated into pro-EPIL and EPIL peptides.
Bellet
D
D
Service de Biologie Oncologique, Institut Gustave-Roussy, Villejuif, France.
Lavaissiere
L
L
Mock
P
P
Laurent
A
A
Sabourin
J C
JC
Bedossa
P
P
Le Bouteiller
P
P
Frydman
R
R
Troalen
F
F
Bidart
J M
JM
D000595:Amino Acid Sequence; D005260:Female; D006133:Growth Substances; D006801:Humans; D007150:Immunohistochemistry; D036341:Intercellular Signaling Peptides and Proteins; D008969:Molecular Sequence Data; D010920:Placenta / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D011247:Pregnancy; D011257:Pregnancy Proteins / Q000235:genetics* / Q000378:metabolism*; D014176:Protein Biosynthesis; D011498:Protein Precursors / Q000235:genetics* / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics*; D014158:Transcription, Genetic
D006133:Growth Substances; C101126:INSL4 protein, human; D036341:Intercellular Signaling Peptides and Proteins; D011257:Pregnancy Proteins; D011498:Protein Precursors; D012333:RNA, Messenger