Molecular cloning of PEC-60 and expression of its mRNA and peptide in the gastrointestinal tract and immune system.
The peptide PEC-60, structurally related to the pancreatic secretory trypsin inhibitor, inhibits glucose-induced insulin secretion. Here we report on the structure of a cDNA clone from pig duodenum encoding PEC-60. The cDNA encodes a 86-amino acid long precursor protein containing a 26-amino acid signal sequence, implying that the mature PEC-60 peptide is secreted from cells. Analysis of porcine duodenum demonstrated a high expression of a 0.6-kilobase long PEC-60 mRNA in this tissue, as well as the presence of strong PEC-60-like immunoreactivity in the cytoplasm of the majority of the goblet cells of the epithelium. High levels of PEC-60 mRNA were also found in the bone marrow and the peripheral blood and moderate levels in the spleen. A strong PEC-60-like immunoreactivity was localized in the monocytes of peripheral blood. Radioimmunoassay revealed high levels of pig PEC-60-like immunoreactivity in pig plasma suggesting that the PEC-60 peptide is efficiently released from cells. These findings imply that the gastrointestinal peptide PEC-60 is formed, stored, and secreted from monocytes present within the bone marrow and in the peripheral blood, indicating a role of the PEC-60 peptide in the immune system in addition to its function as a gastrointestinal peptide.
Metsis
M
M
Department of Medical Chemistry, Karolinska Institute, Stockholm, Sweden.
Cintra
A
A
Solfrini
V
V
Ernfors
P
P
Bortolotti
F
F
Morrasutti
D G
DG
Ostenson
C G
CG
Efendic
S
S
Agerberth
B
B
Mutt
V
V
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D004247:DNA; D004386:Duodenum / Q000378:metabolism*; D004847:Epithelial Cells; D004848:Epithelium / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D006801:Humans; D007107:Immune System / Q000378:metabolism*; D008969:Molecular Sequence Data; D010455:Peptides / Q000235:genetics* / Q000378:metabolism; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000235:genetics*; D011863:Radioimmunoassay; D013552:Swine
C069343:PEC-60 polypeptide; D010455:Peptides; D012333:RNA, Messenger; D004247:DNA