Correlation between immunoglobulin light chain expression and variant translocation in Burkitt's lymphoma

Burkitt's-type lymphomas-leukaemias (BL) are monoclonal proliferations of malignant B lymphocytes. Irrespective of whether they carry the Epstein-Barr virus (EBV) genome, these tumour cells have been shown consistently to have one of the specific reciprocal chromosome translocations, t(8; 14), t(2; 8) or t(8; 22), involving the long arm of chromosome 8 (on 8q24) and chromosome 14, 2 or 22 (on 14q32, 2p12 and 22q11, respectively). The latter chromosomes have been shown recently to carry genes for immunoglobulin (Ig) heavy chains, and kappa and lambda light chains, respectively. Furthermore, the localization of kappa light chains within 2pcen-2p13 encompasses the breakpoint observed in Burkitt's translocation (2p12). It was therefore considered of interest to determine whether the expression of immunoglobulin chains in BL cells is related to the type of chromosomal anomalies observed. We report here that there is a direct relationship between expression of immunoglobulin light chains and specific type of translocation: BL cells with t(8; 22) express lambda chains, whereas those with t(2; 8) express kappa chains.     

Isolation of a gene from Drosophila by complementation in yeast

Transformation of mutant yeast cells by cloned genomic DNA from a higher eukaryote has made it possible to isolate a Drosophila DNA sequence that complements a yeast adenine-8-mutation. A 0.8-kilobase poly(A)-containing RNA is transcribed from the cloned Drosophila segment in transformed yeast cells and can account for functional expression of the gene.     

Inhibition of histamine secretion from mast cells

Histamine secretion from mast cells may be inhibited by elevated intracellular levels of cyclic AMP and by several anti-allergic drugs. These compounds are claimed to act directly on the calcium-gating mechanism activated by the anaphylactic reaction, preventing influx of Ca2+ from the external environment and so blocking exocytosis. To examine this hypothesis further, we have compared here the histamine secretion induced by immunoglobulin E-directed ligands in the presence and absence of added calcium and by the ionophore A23187. Exocytosis evoked by these former agents was originally considered to be almost totally dependent on extracellular calcium but recent studies have shown otherwise. In the absence of added cation, the agents act by mobilizing membrane-bound or intracellular stores of calcium. We show that here that a variety of anti-allergic drugs are potent inhibitors in the conditions used, suggesting that alternative explanations for their action must be sought.