High homology between a trophoblastic protein (trophoblastin) isolated from ovine embryo and alpha-interferons.
Ovine trophoblastic protein B (oTPB), an embryonic protein, is a 20 kDa secretory protein which is synthesized by the ovine conceptus from days 12 to 22 of pregnancy. oTPB was purified by HPLC using ion-exchange chromatography on a DEAE column and was subsequently chromatographed on a reversed-phase column. Automated Edman degradation was then used to determine the N-terminal amino acid sequence up to 45 residues. The sequence data reveal a significant homology between oTPB and bovine interferons alpha of class II: 64% of the amino acids are identical and 75% are homologous. A highly conserved region including residues 23-44 exhibits 82% homology. Identity between oTPB and either HuIFN-alpha.9 or MuIFN alpha.1 is 55%. These alignments between oTPB and IFNs occur at the N-terminus of the mature proteins and proceed without deletion. These results suggest that oTPB is an embryonic interferon.
Charpigny
G
G
Unité d'Endocrinologie de l'Embryon, INRA, Jouy-en-Josas, France.
Reinaud
P
P
Huet
J C
JC
Guillomot
M
M
Charlier
M
M
Pernollet
J C
JC
Martal
J
J
D000595:Amino Acid Sequence; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D004622:Embryo, Mammalian; D005260:Female; D006801:Humans; D007370:Interferon Type I / Q000032:analysis*; D051379:Mice; D008969:Molecular Sequence Data; D010454:Peptide Termination Factors / Q000032:analysis; D011247:Pregnancy; D011257:Pregnancy Proteins / Q000032:analysis*; D012689:Sequence Homology, Nucleic Acid; D012756:Sheep; D013045:Species Specificity
D007370:Interferon Type I; D010454:Peptide Termination Factors; D011257:Pregnancy Proteins; C020947:interferon tau