TRANSCRIPTS FROM OPPOSITE STRANDS OF GAMMA-SATELLITE DNA ARE DIFFERENTIALLY EXPRESSED DURING MOUSE DEVELOPMENT

Using in vitro immune-selected retinoic acid response elements, we hav e isolated mouse genomic clones containing major (gamma) satellite DNA repeats that are considered as typical of chromosome centromeres. Sev eral cDNA clones were then isolated from a F9 cell cDNA library and we re found to harbor variants of the 234-base pair consensus gamma satel lite monomer. In Northern analysis, these satellite DNA sequences hybr idized predominantly to an approximate to 1.8-kb RNA species in polyad enylated RNA from P19 cells. These transcripts were strongly repressed by retinoic acid, and nuclear run-on assays revealed that this repres sion was, at least in part, mediated at the transcriptional level. Sat ellite transcripts were also detected in HeLa cells, where they were s imilarly 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 hybridiza tion analysis revealed that satellite transcripts are generated from o pposite DNA strands and are differentially expressed in cells of the d eveloping central nervous system as well as in adult liver and testis. These data may have implications on retinoic acid-mediated transcript ional regulation and centromere function.