Adenylate-rich sequences of heterogeneous nuclear RNA from normal and chronic lymphocytic leukaemia lymphocytes

Rapidly labelled high molecular weight heterogeneous nuclear RNA (Hn RNA) from normal and chronic lymphocytic leukaemia (CLL) lymphocytes has been fractionated into two classes by chromatography on poly (U) sephasose. The (+) Hn RNA is bound to poly (U) sepharose and contains both a long poly (A) segment (100-200 nucleotides) and shorter (A) rich sequences (approximately 20-30 nucleotides. (-) Hn RNA is not bound to poly (U) sepharose and lacks the longer poly (A) segment but does contain shorter (A) rich sequences. Partial association of the short (A) rich segments with double-stranded regions was found for both classes of Hn RNA but was most pronounced in (-) Hn RNA from high WBC cases of CLL. Both classes of Hn RNA from CLL lymphocytes contain varying but generally higher amounts of the short (A) rich fraction than those in normals. Similar amounts of the longer poly (A) segments were found in (+) Hn RNA from both CLL and normal lymphocytes.