CLONING OF THE MURINE TRANSCRIPTIONAL COREPRESSOR COMPONENT SAP18 ANDDIFFERENTIAL EXPRESSION OF ITS MESSENGER-RNA IN THE HEMATOPOIETIC HIERARCHY

A differentially expressed sequence tag (EMegR4) was isolated from a s ubtractive hybridization between a single bipotent erythroid/megakaryo cytic precursor (E/Meg) and a single bipotent neutrophil/macrophage pr ecursor (N/M). It was used to clone a novel murine cDNA referred to as mSAP18. The full-length mSAP18 cDNA contains 3415 nucleotides and cod es for a protein of 153 amino acids. The open reading frame shows 98 % identity to a human protein, SAP18, recently identified in a complex with the transcriptional corepressor mSin3 and histone deacetylase. mS AP18 cDNA harbours four polyadenylation sites and a B2 small intersper sed repetitive element (SINE) in its 3' untranslated region. We demons trate that mSAP18 RNA is expressed with stage and lineage specificity in the hematopoietic hierarchy, and that alternative polyadenylation s ites are used. (C) 1998 Elsevier Science B.V.