We have examined whether transfected mouse erythroleukaemia (MEL) cells can be used to examine differential expression of human gamma- and beta-globin genes. These cells, which express only their adult globin genes, will transcribe the human adult beta gene but not the fetal gamma genes when they are introduced on an intact human chromosome 11 by cell fusion. However, MEL cells stably transfect...

A monoclonal antibody which blocks InsP(3)-induced Ca(2+) release from isolated endoplasmic reticulum was used to isolate a novel 4.0 kb cDNA from a human erythroleukaemia (HEL) cell cDNA expression library. A corresponding mRNA transcript of approx. 4.2 kb was present in all human cell lines and tissues examined, but cardiac and skeletal muscle had an additional transcript of 6.4 kb. The ident...

Murine erythroleukaemia cells (MELC) are erythroid precursor cells that undergo erythroid differentiation in the presence of the inducer hexamethylene bisacetamide (HMBA). The effects of lead on haem biosynthesis in MELC following HMBA-induced differentiation were studied. MELC were induced with HMBA in the presence of 20, 40 and 80 mum-lead acetate and cell density, haem content, incorporation...

Here we report that the slow-transforming helper component of Friend murine leukaemia virus (Fr-MLV), which produces lymphoid leukaemias in normal mice, induces erythroleukaemia in mice given syngeneic pituitary grafts (SPG). Newborn mice were infected with Fr-MLV and, at one month of age, were transplanted with two pituitary glands under the kidney capsule. Sham-operated infected mice and unin...

Although the adaptive immune response almost invariably fails to completely eliminate retroviral infections, it can exert significant protection from disease and long-term control of viral replication. Friend virus (FV), a mouse retrovirus, causes persistent infection in all strains of mice and erythroleukaemia in susceptible strains, the course of which can be strongly influenced by both genet...

Mitochondrial chelatable ("redox-active") iron is considered to contribute to several human diseases, but has not yet been characterized in viable cells. In order to determine this iron pool, we synthesized a new fluorescent indicator, rhodamine B-[(1,10-phenanthrolin-5-yl)aminocarbonyl]benzyl ester (RPA). In a cell-free system, RPA fluorescence was strongly and stoichiometrically quenched by F...

SWI/SNF complexes are involved in both activation and repression of transcription. While one of two homologous ATPases, Brg1 [Brm (Brahma)-related gene 1] or Brm, is required for their chromatin remodelling function, less is known about how these complexes are recruited to DNA. We recently established that a DNA-binding complex containing TAL1/SCL, E47, GATA-1, LMO2 and Ldb1 stimulates P4.2 (pr...