A cDNA encoding a new member of the rat placental lactogen family, PL-I mosaic (PL-Im)

M. Hirosawa, R. Miura, K. S. Min, N. Hattori, K. Shiota*, T. Ogawa

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

38 Citations (Scopus)


We have isolated a cDNA encoding a novel placental lactogen (PL), PL-I mosaic (PL-Im), by screening the cDNA library in λZAP of the mid-pregnant (day 12) rat placenta. The cDNA comprised an open reading frame of 687 bp encoding 229 amino acids, in which there were two putative N-glycosylation sites. Northern blot analysis showed that PL-Im mRNA was expressed specifically during mid-pregnancy (days 10 and 12) in the rat placenta. The cDNA was highly homologous with those of other rat PL family members; in particular, the homology among PL-Im, PL-I (mid-pregnancy-specific) and PL-Iv (late-pregnancy-specific) was over 90%. Interestingly, the nucleotide sequence of PL-Im cDNA was a mosaic of PL-I and PL-Iv and it did not possess its own particular sequence. As the genomic pattern determined using Southern blot analysis of PL-Im was distinct from that of PL-I and PL-Iv, the encoded area of PL-Im appears to be independent of those of PL-I and PL-Iv on the gene. In the dendrogram of the rat PL family constructed on the basis of the nucleotide sequence homologies, PL-Im was located between PL-Iv and PL-I in the process of molecular evolution. Therefore, PL-Im has a unique cDNA structure and may be a principal factor in the molecular evolution of PLs.

Original languageEnglish
Pages (from-to)387-397
Number of pages11
JournalEndocrine Journal
Issue number4
Publication statusPublished - 1994
Externally publishedYes


  • cDNA
  • cloning
  • placental lactogen I mosaic
  • rat placental lactogen

ASJC Scopus subject areas

  • Endocrinology


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