ABSTRACT
Treatment of sensitive EL4 mouse thymoma cells with phorbol esters causes growth inhibition, adherence to substrate and production of several lymphokines including Interleukin 2. Resistant cells lack all of these responses. Since production of Interleukin 2 mRNA is dependent on protein synthesis, and the Interleukin 2 gene has a phorbol ester responsive element, we examined both cell lines for expression of the various Jun and Fos species which bind to this element. Phorbol ester induced c-fos, jun-B, and jun-D RNAs within 20 min in both cell lines. Fos-B was similarly induced in sensitive cells but induction was delayed and greatly enhanced in resistant cells. C-jun RNA induction was detected only in sensitive cells. Western analysis confirmed the induction of c-Jun and a Fos-related protein in sensitive cells only. Southern analysis indicated that both cell lines contain c-jun and fra-1 genes. These results suggest that defective induction of c-Jun and/or Fos-related proteins may contribute to the absence of phorbol ester-induced lymphokine production in resistant EL4 cells.
Subject(s)
DNA-Binding Proteins/biosynthesis , Phorbol Esters/pharmacology , Proto-Oncogene Proteins/biosynthesis , Thymoma/metabolism , Thymus Neoplasms/metabolism , Transcription Factors/biosynthesis , Animals , Base Sequence , Blotting, Western , DNA/analysis , DNA-Binding Proteins/genetics , Drug Resistance , Gene Expression , Interleukin-2/biosynthesis , Interleukin-2/genetics , Kinetics , Mice , Molecular Sequence Data , Nucleic Acid Hybridization , Oligonucleotide Probes , Proto-Oncogene Proteins/genetics , Proto-Oncogene Proteins c-fos , Proto-Oncogene Proteins c-jun , RNA/biosynthesis , Transcription Factors/genetics , Tumor Cells, CulturedABSTRACT
The red blood cells of normal adult ducks contain two main hemoglobins. The most abundant type, HbA, comprises approximately 80% of the total, with the remaining 20% being made up of HbD. An attempt was made to determine whether during hemolytic anemia a special alpha globin chain (alpha s) replaces the alpha chain of HbA found in normal animals. This special stress alpha globin, whose existence has been seriously questioned, was originally postulated to explain the sequence discrepancies obtained between alpha chains of normal and anemic chickens and ducks. Using gel electrophoresis, isoelectric focusing, and HPLC peptide mapping techniques no qualitative differences between the alpha A globins of normal and anemic animals were found. The nature of the beta globin chains present in adult ducks has also never been rigorously established. In this work, a variety of techniques, including HPLC, gel electrophoresis, and microcolumn amino acid analysis, were used to examine the beta chains from each hemoglobin. Using these methods, no differences were found between the beta globin chains of the two hemoglobins.
Subject(s)
Anemia, Hemolytic/blood , Ducks/blood , Globins/genetics , Hemoglobins/genetics , Amino Acids/blood , Anemia, Hemolytic/chemically induced , Animals , Chemical Phenomena , Chemistry , Chromatography, High Pressure Liquid , Disease Models, Animal , Ducks/genetics , Hemoglobin A/genetics , Hemoglobins, Abnormal/genetics , Peptide Fragments/bloodABSTRACT
Normal adult ducks possess two main types of hemoglobin: a major species (80%), HbI (alpha I2 beta I2), and a minor species (20%), HbII (alpha II2 beta II2). We have cloned recombinant cDNAs for the duck globin mRNAs using the ribosubstitution floppy loop technique. We present here the sequence for a duck alpha globin mRNA closely related to the chicken alpha D globin mRNA. Our new sequence data also include the 5' noncoding regions of the duck alpha A, alpha D, and beta globin mRNAs. Analysis of the untranslated regions of these mRNAs reveals several conserved sequences which may be important in the regulation of gene expression.
