Reproduction Abstracts

Introduction: Trophoblast stem (TS) cells are capable of differentiating into all subtypes of trophoblast cells. Lin28a, an RNA-binding protein involved in the post-transcriptional regulation of gene expression, is highly expressed in undifferentiated TS cells but is greatly reduced in its expression in differentiated trophoblast cells. Lin28a is known as a major factor controlling growth and metabolism through regulation of the maturation of let-7 microRNA. Considering that Lin28a binds to mRNA as well, it was assumed that Lin28a also regulates gene expression independent of let-7. In this study, we aimed to identify mRNAs that interact with Lin28a in TS cells.

Material and methods: We performed RNA-immunoprecipitation sequencing analysis using anti-Lin28a antibody and TS cell extract. Expression levels of Lin28a-associated mRNA candidates were analyzed in a Lin28a-knockdown TS cell line.

Results and discussion: Anotated functions of the proteins encoded by Lin28a-associtated mRNAs were diverse. A transcription factor Cdx2 that is essential for the maintenance of TS cells was included in these mRNAs. Knockdown of Lin28a in TS cells caused decrease in the expression level of Cdx2. Thus, Lin28a interacts with various mRNAs, and possibly control many physiological functions in TS cells.