Developmental expression profile of the YY2 gene in mice.

The transcription factor Yin Yang 2 (YY2) shares a structural and functional highly homologue DNA-binding domain with the ubiquitously expressed YY1 protein, which has been implicated in regulating fundamental biological processes. However, the biological relevance of YY2 has not been identified yet. Towards the understanding of YY2 biology, we analyzed in detail the expression pattern of yy2 in various organs during embryonic and postnatal mouse development till adulthood. Thereby, a constant yy2 level was detected in heart and lung tissue, whereas in different brain regions yy2 expression was dynamically regulated. Interestingly, in any analyzed tissue neither the homologue yy1 nor the mbtps2 gene showed changes in mRNA expression levels like yy2, although the intronless yy2 gene is located within the mbtps2 locus.Furthermore, we detected yy1, yy2, and mbtps2 mRNA in primary mouse neurons, microglia cells, and astrocytes. In comparison to yy2 and mbtps2, yy1 revealed the highest expression level in all cell types. Again, only yy2 showed significantly altered gene expression levels among the cell types. Higher yy2 expression levels were detected in microglia cells and astrocytes than in primary neurons. Yy2 expression in the heart and lung is constitutively expressed during embryogenesis and in adult mice. For the first time, developmental changes of yy2 transcription became obvious in various areas of the brain. This suggests that yy2 is involved in developmental gene regulation.