GENE-EXPRESSION IN RESPONSE TO RETINOIC ACID IN NOVEL HUMAN-CHROMOSOME-21 MONOCHROMOSOMAL CELL HYBRIDS

To access a wide variety of expressed sequences from human chromosome 21 we have placed this chromosome into undifferentiated P19 mouse embr yonic carcinoma cells. Cell lines resulting from these experiments hav e a range of morphologies and a wide variety of karyotypes. We have st udied the retinoic acid response of five cell lines, compared to P19 c ells, by observing three markers of retinoic acid induced P19 differen tiation-cell morphology, RAR alpha and Wnt1 transcription. We see an ' early' retinoic acid response effect, however this response breaks dow n by the time the 'late' gene Wnt1 would be transcribed in P19 cells. A highly responsive cell line will be useful for cloning expressed seq uences from human chromosome 21 which are produced by early genes in r etinoic acid inducible pathway, such as those involved in neurogenesis .