Binding affinity of leucine-containing chromatin proteins to the polytene X chromosome of Drosophila hydei and its significance.

Association of newly synthesised non-histone chromosomal protein to the polytene X chromosome of larval salivary glands of D. hydei has been examined by autoradiographic procedure using 3H-leucine. It has been observed that 3H-leucine labelling pattern is inhibited in presence of puromycin. Results further reveal that there is a reasonable concordance between the binding affinity of newly synthesized protein on the single X chromosome of the male and paired X's of the female. A sitewise analysis of 3H-leucine labelling reveals that although 3H-leucine incorporation pattern are not strictly comparable with 3H-RNA synthesis pattern observed under in vivo transcription condition, the labelling pattern with 3H-leucine are not merely the reflection of mass distribution of protein in the polytene chromosomes. Certain aspects of regulation in the organisation of male and female X chromosome in Drosophila by de novo synthesis of protein are discussed.