Identification and characterization of a serpin with differential expression during the life cycle of the sea lamprey.
We have cloned a member of the serine proteinase inhibitor gene superfamily from the sea lamprey, Petromyzon marinus. The predicted translation product contains a putative signal peptide and mRNA expression is localized mainly to the liver. Northern blot analysis indicates that the mRNA increases in the larvae and peaks in late larval life. At the onset of metamorphosis there is a approximately 10-fold drop after which it remains low. These changes correspond with levels of circulating thyroid hormone suggesting that this serpin is involved in or regulated by molecular signals that induce metamorphosis in the lamprey. Use of alignments and structural information from other serpins indicates that the lamprey serpin has the potential to be inhibitory. In addition the lamprey serpin contains methionine and serine at the P1 and P1' positions, respectively. Appropriate residues at positions important in allowing the insertion of strand s4A into beta-sheet A that occurs upon cleavage in inhibitory serpins are also found in the lamprey serpin.
Robson
P
P
Division of Cardiovascular Research, Hospital for Sick Children, Toronto, Canada.
Li
F
F
Youson
J H
JH
Keeley
F W
FW
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D017931:DNA Primers / Q000235:genetics; D018076:DNA, Complementary / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D007798:Lampreys / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D007814:Larva / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008675:Metamorphosis, Biological; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D011487:Protein Conformation; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D015843:Serpins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D013045:Species Specificity
D017931:DNA Primers; D018076:DNA, Complementary; D012333:RNA, Messenger; D015843:Serpins