title: RNase H of human leukemic cells: a new biological parameter in the study of human leukemias (review).
abstract: This article reviews the authors' investigation of the enzyme RNase H (EC 3.1.4.34.) in human leukemic cells and presents the accumulated available data, based on which this enzyme is proposed to serve as a new biological parameter in the study of progression of human leukemias. The introduction gives a brief account of the occurrence, characterization and possible biological role of RNase H in cells and in retroviruses. The results reviewed briefly concern: (1) the development of a new convenient, economic and reliable assay for normal and leukemic blood mononuclear cell RNase H, which is capable of resolving subtle activity differences between samples; (2) the differentiation of RNase H levels between normal and leukemic cells; (3) the correlation of RNase H levels from different leukemia types with the severity of the disease; (4) the correlation of RNase H levels in leukemic cells with clonogenic stages in the clonal differentiation pathway; (5) the predictive potential of a RNase H activity-based parameter (phi) in assessing progression in acute myelocytic leukemia and (6) the possibility of differentiation of the RNase H levels between normal and leukemic cells via regulation of the enzyme activity at the level of antagonistic phosphorylations mediated by cAMP and calmodulin.
authors.affiliation: Department of Experimental Physiology, University of Athens, School of Medicine, Greece.
authors.forename: A D
authors.initials: AD
authors.lastname: Papaphilis
authors.forename: E F
authors.initials: EF
authors.lastname: Kamper
authors.forename: S
authors.initials: S
authors.lastname: Grammenou
authors.forename: C
authors.initials: C
authors.lastname: Kattamis
authors.forename: G A
authors.initials: GA
authors.lastname: Pangalis
mesh_terms: D004722:Endoribonucleases / Q000032:analysis* / Q000037:antagonists & inhibitors / Q000502:physiology; D006801:Humans; D007938:Leukemia / Q000201:enzymology* / Q000473:pathology; D007963:Leukocytes, Mononuclear / Q000201:enzymology; D014411:Neoplastic Stem Cells / Q000201:enzymology; D016914:Ribonuclease H
chemical_list: D004722:Endoribonucleases; D016914:Ribonuclease H