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Biomedical subjects

A Donelli

Publications and source records attributed to A Donelli.

30 records · Page 2Linked to original sources
PubMed1985

Expression of human c-fes onc-gene occurs at detectable levels in myeloid but not in lymphoid cell populations.

Total cellular RNA from a variety of myeloid and lymphoid cell populations, normal and leukaemic, was analysed for the expression of a human cellular onc-gene, c-fes, by northern blot hybridization assays. The probe used was a molecularly cloned human DNA sequence homologous to the 5' terminal sequence of v-fes. All the myeloid cellular populations expressed the c-fes gene. In some cell populations at an advanced stage of differentiation (circulating leucocytes from Chronic myeloid leukaemia (CML), HL60 cells induced to differentiate by retinoic acid) the level of expression was even higher than in early stages of the myeloid lineage (blast cells from AML, uninduced HL60 cells). No transcript of the c-fes gene was detected in the different lymphoid populations studied. The occurrence of an RNA complementary to the c-fes sequence appears sufficiently characteristic of a myeloid population to distinguish it from a lymphoid population, normal and leukaemic.

Cell Differentiation↗
PubMed1985

Activation of c-myb expression by phytohemagglutinin stimulation in normal human T lymphocytes.

The expression of c-myb in normal human T lymphocytes directly derived from a normal subject and not adapted to continuous growth in culture was found to be markedly increased after phytohemagglutinin stimulation. In the same cells, the expression of c-myc mRNA is a much earlier event compared with the appearance of c-myb mRNA, which takes place soon after that of histone H3 mRNA. The increase in c-myb expression was not due to a particular T-lymphocyte subset, as shown by in situ hybridization assays.

Cells, Cultured↗
PubMed1984

Sequence complexity and diversity of polyadenylated RNA molecules transcribed in human myeloid cells. Leukemic myeloblasts and HL60 promyelocytes uninduced and induced to terminal differentiation with retinoic acid.

The kinetic composition of the polyadenylated RNAs of leukemic myeloblasts and HL60 promyelocytes was examined by the cDNA-poly (A) +RNA reassociation technique before and after the induction of differentiation with retinoic acid. The data obtained in the homologous hybridizations show the following main features: the sequence complexity of the total poly(A) +RNA molecules is 72,000 different sequences in leukemic myeloblasts, 64,000 in HL60 promyelocytes before induction and 26,000 after treatment of HL60 with retinoic acid; the number of sequences reacting as abundant is clearly higher in HL60 promyelocytes (5,000) than in leukemic myeloblasts (1,000), and the number decreases sharply after induction (300); the repetition frequency of the abundant and rare components is almost unchanged between leukemic myeloblasts and HL60 promyelocytes, while it is markedly increased after induction with retinoic acid. The heterologous reactions show that the observed differences in complexity are mainly related to the missing of rare sequences. Moreover, an important portion of sequences already present in leukemic myeloblasts has a definitely higher repetition frequency in HL60 promyelocytes. Finally, the most abundant sequences in HL60 cells after induction are already present before treatment. The data presented here suggest that, during human myeloid differentiation, important, possibly transcriptional, regulatory mechanisms of gene expression are active long after the first commitment event of the hemopoietic undifferentiated stem cell.

Adult↗
PubMed1981

Sequence complexity and diversity of polyadenylated RNA molecules of human normal resting, PHA-stimulated and leukemic lymphocytes.

The abundance and complexity of total poly(A)+RNA of human normal unstimulated lymphocytes, PHA-stimulated and leukemic lymphocytes were examined using the cDNA-poly(A)+ RNA hybridization technique. It was found that in both PHA-stimulated and leukemic lymphocytes the complexity of total poly(A)+RNA is strongly reduced in respect to normal unstimulated lymphocytes. The differences is due to a small portion, by weight, of high complexity sequences, suggesting the involvement or nuclear, not necessarily transcriptional, events. Moreover the heterologous hybridizations show that: 1) in PHA-stimulated lymphocytes there is a set of highly abundant sequences which are represented in normal and leukemic lymphocytes at a very reduced rate; 2) the sequences abundant in normal unstimulated lymphocytes are less represented in leukemic lymphocytes; the converse also is true, but at a lower extent. On the basis of available data, it is suggested that the observed changes in the abundance pattern of PHA-stimulated lymphocytes may be related mainly to a difference in the half-life of the mRNAs, while those of leukemic lymphocytes require some transcriptional or post-transcriptional nuclear event.

Base Sequence↗
PubMed1979

Kinetics of hybridization to human DNA of heterogeneous nuclear RNA isolated from normal human lymphoblasts and acute leukemia blast cells.

Heterogeneous nuclear RNA was extracted from normal PHA-stimulated human lymphocytes and acute myeloid leukemia blast cells. Experiments were performed to determine the hybridization kinetics of these RNA's to human DNA. The best least squares solutions indicate in the hybridization reaction of both normal and leukemic RNA two main components. For leukemic cell RNA the rate constants of both components were significantly different from that of normal cell RNA. In particular, the difference between the rate constants of the second lower component suggests that the slowly hybridizing sequences in leukemic cell RNA have a degree of repetition higher than of the corresponding sequences of normal cell RNA.

Base Sequence↗