A quantitative study of histones of meiocytes

The existence of a meiocyte-specific histone fraction (FM) (Sheridan and Stern, 1967) is confirmed. FM appears during premeiotic interphase and prophase I in Lilium candidum in addition to a set of standard somatic fractions. Several pieces of evidence were obtained showing that FM can not be an aggregate of non-histone protein with some histone fraction. If the amount of somatic fractions in the total histone is taken as 100% then the relative content of any somatic fraction remains constant (with insignificant fluctuations around the constant level) during the whole period of the rise and fall of FM. Thus, FM appears not at the expence but in excess of somatic fractions, i.e. FM is an extra histone and the resulting histone content of the meiocytes in pachytene is higher than that of somatic and sporogenous cells during mitosis. — The relative amount of FM increase during prophase I reaches a maximum of about 14% over the sum of somatic histone fractions at zygotene-pachytene, and falls to 7% at meiotic divisions. These events coincide with the rise and fall of the synaptonemal complex, and it is therefore the suggested that FM is one of the molecular components of a synaptonemal complex.Dedicated to Professor A. A. Prokofieva-Belgovskaia on the occasion of the seventieth anniversary of her birthday.