Open AccessGlobin chain synthesis in single erythroid bursts from cord blood: studies on gamma leads to beta and G gamma leads to A gamma switches.
Author(s) -
Paola Comi,
Barbára Giglioni,
Sergio Ottolenghi,
AM Gianni,
E. Polli,
Pasquale Barba,
A. Covelli,
Giovanni Migliaccio,
M Condorelli,
Cesare Peschle
Publication year - 1980
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.77.1.362
Subject(s) - globin , beta (programming language) , alpha (finance) , isoelectric focusing , gamma ray , gamma globulin , cord blood , microbiology and biotechnology , biology , physics , biophysics , radiochemistry , hemoglobin , chemistry , biochemistry , genetics , nuclear physics , medicine , antibody , construct validity , enzyme , nursing , computer science , patient satisfaction , programming language
Erythroid bursts from cord or adult blood were grown in methylcellulose cultures (3 international units of erythropoietin per plate). On day 13, single bursts were picked up and reincubated for 16-24 hr with [3H]leucine. Radioactive globin chains [alpha,beta,G gamma, and A gamma (Ala-136)] were analyzed by either isoelectric focusing on polyacrylamide gels and fluorography or carboxymethylcellulose chromatography. In all cases, alpha to non-alpha globin radioactivity ratios were close to 1. In single cord blood bursts, the values of both gamma-to-beta and G gamma-to-A gamma ratios were spread over a large spectrum and further characterized by a continuous rather than a bimodal distribution. Morever, the G gamma-to-A gamma ratios demonstrated in single bursts appeared to be directly correlated with the respective gamma-to-beta ratios. These data suggest that both the gamma leads to beta and the G gamma leads to A gamma switches are mediated via mechanisms modulating the relative activities of the different genes in the non-alpha globin gene cluster rather than via selection of clones committed to the preferential synthesis of beta and A gamma globins. In contrast with the results obtained with cord blood, individual adult blood bursts synthesize a lower and hence relatively more uniform amount of gamma globin chains.