Stage-specific expression and localization of MENT, a nuclear protein associated with chromatin condensation in terminally differentiating avian erythroid cells.
Polyclonal antibodies have been raised against a non-histone protein (MENT) which has been previously shown to be associated with the repressed chromatin of mature chicken erythrocytes and to promote the in vitro condensation of chromatin of immature erythrocyte nuclei. Here we report that the expression pattern of MENT closely follows chromatin condensation in maturing avian erythrocytes of definitive and primary lineages. Accumulation of MENT correlates more strongly with chromatin condensation than does accumulation of histone H5. In addition to being present in erythrocytes, the protein was also found in neutrophil nuclei and an immunofluorescence reaction was observed with embryonic (nucleated) thrombocytes. MENT was not detected in other chicken tissues (brain, liver, testis). In intact erythrocytes, MENT immunofluorescence was found in foci close to the nuclear periphery, while in isolated, decondensed nuclei, the fluorescence signal was uniformly distributed. In neutrophil nuclei, containing approximately 10 times more MENT than adult erythrocytes, intense staining associated with the peripheral heterochromatin was observed. These findings are discussed in regard to a possible mechanism for chromatin condensation by MENT.
Department of Biology, University of Massachusetts, Amherst 01003.
S A
SA
Grigoryev
C L
CL
Woodcock
D000818:Animals; D000906:Antibodies; D030161:Avian Proteins; D015153:Blotting, Western; D001921:Brain / Q000378:metabolism; D002454:Cell Differentiation; D002467:Cell Nucleus / Q000378:metabolism; D002478:Cells, Cultured; D002642:Chick Embryo; D002645:Chickens; D002843:Chromatin / Q000378:metabolism*; D002868:Chromosomal Proteins, Non-Histone / Q000032:analysis / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D004912:Erythrocytes / Q000166:cytology / Q000378:metabolism*; D004920:Erythropoiesis; D008099:Liver / Q000378:metabolism; D008297:Male; D008970:Molecular Weight; D009928:Organ Specificity; D010446:Peptide Fragments / Q000302:isolation & purification; D013737:Testis / Q000378:metabolism
D000906:Antibodies; D030161:Avian Proteins; D002843:Chromatin; D002868:Chromosomal Proteins, Non-Histone; C081441:MENT protein, Gallus gallus; D010446:Peptide Fragments