Temporally Regulated Expression of Lin-28 in Diverse Tissues of the Developing Mouse

Gene Expr Patterns. 2003 Dec;3(6):719-26. doi: 10.1016/s1567-133x(03)00140-6.

Abstract

The gene lin-28 was originally identified through a mutant of the nematode Caenorhabditis elegans displaying defects in developmental timing. It is expressed stage-specifically in tissues throughout the animal and is required for cell fates to be expressed at the appropriate stage of larval development. lin-28 encodes a cytoplasmic protein with a unique pairing of RNA-binding motifs. Diverse animals possess Lin-28 homologues and mouse Lin-28 is expressed in embryos, embryonic stem cells and embryonal carcinoma cells, but not in some differentiated cell types. To assess whether mammalian Lin-28 may function as a developmental timing regulator, we examined adult and embryonic tissues of the mouse for its expression. We observed Lin-28 protein in many diverse tissues of the embryo through the period of organogenesis and that it persists in some tissues in the adult. In addition to an overall down-regulation during embryogenesis, in at least two tissues Lin-28 expression shows temporal regulation, as opposed to cell type or tissue-specific regulation: in the developing bronchial epithelium, where it is present in the developing lung and absent in the adult, and in a subset of cells developing along the crypt-villus axis of the intestine. Interestingly, unlike epithelia, cardiac and skeletal muscle continuously express Lin-28, suggesting an ongoing need for its activity there. We also observed that Lin-28 expression is repressed during the retinoic acid-induced differentiation of mouse P19 cells into neuronal cells, suggesting that down-regulation of Lin-28 in some tissues may occur in response to hormonal signals that govern development.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Cell Line, Tumor
  • Down-Regulation
  • Immunohistochemistry
  • Kinetics
  • Mice / anatomy & histology
  • Mice / embryology*
  • Mice / metabolism
  • RNA-Binding Proteins / immunology
  • RNA-Binding Proteins / metabolism*

Substances

  • Lin-28 protein, mouse
  • RNA-Binding Proteins