PURIFICATION AND CHARACTERIZATION OF A NOVEL ACID-SOLUBLE NUCLEAR-PROTEIN FROM DEVELOPING EMBRYOS OF THE CAMEL TICK HYALOMMA-DROMEDARII (ACARINA, IXODIDAE)

A novel acid-soluble protein has been extracted from nuclei of develop ing embryos of H. dromedarii ticks and purified to homogeneity. This t ick embryo basic protein (TEBP) was predominant during the cleavage st age of tick embryogenesis, whereas the complete set of histones was de tectable at the late cleavage stage. The amount of TEBP reaches a maxi mum value at day 9 after oviposition. Thereafter, the original N-termi nal dipeptide (leucine-serine) is eliminated. This coincides with the start of organogenesis. In spite of its low molecular mass, TEBP seems to be related to histone H1 in some properties such as solubility in perchloric acid and binding affinity to DNA. A task for the future wil l be to define the role of this protein as a counterpart of the histon es for the genome organization during embryogenesis.