The occurrence and possible significance of haemoglobin in the chromosomal regions of mature erythrocyte nuclei of the newt Triturus cristatus cristatus.

Absorption measurements in violet light (lambda 4047 A) of thin sections of mature newt erythrocytes have indicated the presence of a haem compound, probably haemoglobin, within the chromosomal regions of the nucleus. The amount is about 45 per cent of that in the cytoplasm. The possible significance of this nuclear haemoglobin in determining nuclear structure is discussed in terms of the electrostatic interaction of haemoglobin and nucleohistone.