Raymond M Withy

Recombinant human erythropoietin

A rodent epithelioid cell transformed with a recombinant DNA vector including a DNA sequence encoding human erythropoietin is capable of producing N-linked and O-linked glycosylated human erythropoietin.

Sequence and structural relationships in the cytokine family

The sequences of nine different cytokines, growth hormone, and prolactin have been aligned and their secondary structure predicted. The alignment reveals that each exon has a characteristic sequence pattern shared by all cytokines. The most striking sequence similarity is observed in exon 4, where the residue pair Phe-Leu is conserved in many cytokines. In addition, there are discreet homologous regions between two specific growth factors, including a high degree of homology between granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin 3 (IL-3). The secondary structure analysis predicts that exon 3 of all cytokines has an antiparallel helix-turn-helix motif, which is likely to form the central helical segments of a four α-helical bundle-type structure. Based on the secondary structure and the disulfidebonding pattern, the topological connectivity for a number of cytokines has been predicted.

Tissue sources of murine megakaryocyte potentiator: biochemical and immunological studies

Summary. The immunological and biochemical characteristics of murine megakaryocyte potentiator from lung and bone marrow were examined and compared with thrombopoietic stimulatory factor. Biological activity was not neutralized by anti‐erythropoietin, but megakaryocyte potentiator activity from all three sources was abolished or reduced when the preparations were treated with anti‐thrombopoietic stimulatory factor or anti‐interleukin‐6. Megakaryocyte potentiator levels in lung conditioned medium were not found to be enhanced from mice treated with lipopolysaccharide, in contrast to granulocyte‐macrophage colony‐stimulating factor (GM‐CSF) levels. The biochemical properties of murine megakaryocyte potentiator from lung and bone marrow were compared and found to be similar in the elution profiles from anion exchange, gel filtration and reversed phase liquid chromatography. It is concluded that the activities in lung and bone marrow are very similar if not identical, to interleukin‐6.