Differences among the polyadenylated RNA sequences of human leucocyte populations: an approach to the objective classification of human leukaemias

We have constructed a complementary DNA (cDNA) library representing expressed sequences of the white blood cells from a patient with chronic granulocytic leukaemia. The library was screened by colony hybridization of 32P-labelled cDNAs synthesized from the polyadenylated RNAs of the white blood cells from patients with chronic granulocytic or chronic lymphocytic leukaemia. The autoradiographic patterns were compared and 70 recombinants were selected to comprise a panel which distinguished between these two types of leukaemia. Hybridization of this panel with complementary DNAs transcribed from the polyadenylated RNAs of a variety of normal and neoplastic leucocyte populations showed that the RNA sequences in high abundance in leucocytes from chronic granulocytic leukaemias differ quite radically from those in other leucocytes. The patterns of hybridization seen when this panel was challenged with cDNAs representing the RNAs of normal and leukaemic leucocyte populations were sufficiently different to distinguish clearly the peripheral blood leucocytes of chronic granulocytic leukaemias from other populations of white blood cells, both normal and leukaemic. We suggest that this approach might provide additional markers useful in the classification of the acute leukaemias, especially the undifferentiated leukaemias whose identification by conventional methods is uncertain.     

The synthesis of polydeoxyribonucleotide by cell-free extracts of embryonic mouse tissue

The conditions under which soluble extracts prepared from mouse embryos incorporate [(3)H]thymidine 5'-triphosphate into polydeoxyribonucleotide have been studied. In common with similar preparations from other mammalian tissues, mouse-embryo DNA nucleotidyltransferase requires the four complementary deoxyribonucleoside 5'-triphosphates, primer DNA and a bivalent cation for activity. Unlike other mammalian DNA nucleotidyltransferases, the rate and extent of the incorporation of [(3)H]thymidine 5'-triphosphate is much greater with Mn(2+) than with Mg(2+) and, with either Mg(2+) or Mn(2+), maximum activity occurs at pH6.4. The difference between Mg(2+) and Mn(2+) varies markedly with pH, reaching a maximum of six- to eight-fold at pH6.4.     

Changes induced in rat liver polysomal polyadenylated RNAs by depletion of circulating glucocorticoids.

The effects of adrenalectomy on the complexity and the relative abundances of rat liver polyadenylated mRNAs have been investigated. The qualitative and quantitative changes induced by adrenalectomy have been measured by hybridisation of polysomal polyadenylated RNAs from the livers of normal and adrenalectomised rats with total cDNAs, fractionated cDNAs, cDNA representing RNAs specific to normal liver, total unique-sequence DNA and unique-sequence DNA complementary to normal liver polysomal RNA. These analyses indicated that, by 14 days after adrenalectomy, the equivalent of about 7000 sequences of average length 2000 nucleotides can no longer be detected in liver polysomes. Many other sequences are decreased in abundance as compared to normal liver, but some abundant sequences become more abundant. Administration of a glucocorticoid hormone (dexamethasone) very rapidly reverses these changes.