Transcripts from opposite strands of gamma satellite DNA are differentially expressed during mouse development

Using in vitro immuno-selected retinoic acid response elements, we have isolated mouse genomic clones containing major (gamma) satellite DNA repeats that are considered as typical of chromosome centromeres. Several cDNA clones were then isolated from a F9 cell cDNA library and were found to harbor variants of the 234-base pair consensus gamma satellite monomer. In Northern analysis, these satellite DNA sequences hybridized predominantly to an approximately 1.8-kb RNA species in polyadenylated RNA from P19 cells. These transcripts were strongly repressed by retinoic acid, and nuclear run-on assays revealed that this repression was, at least in part, mediated at the transcriptional level. Satellite transcripts were also detected in HeLa cells, where they were similarly down-regulated by retinoids. Heterogeneously sized satellite transcripts were detected in RNA from specific mouse tissues, such as fetuses (but not placenta), adult liver, and testis. In situ hybridization analysis revealed that satellite transcripts are generated from opposite DNA strands and are differentially expressed in cells of the developing central nervous system as well as in adult liver and testis. These data may have implications on retinoic acid-mediated transcriptional regulation and centromere function.