Sites of in Vivo Acetylation in Trout Testis Histone IV

E.P.M Candido,Gordon H Dixon

doi:10.1016/s0021-9258(18)62212-4

E.P.M Candido, Gordon H Dixon

Open Access

https://doi.org/10.1016/s0021-9258(18)62212-4

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Abstract

During the process of spermatogenesis in rainbow trout, there is extensive acetylation of some histone fractions. A large proportion of the acetyl groups is present in histone IV, and the sites of acetylation in this fraction have been determined. Four lysyl residues in the NH2-terminal region at positions 5, 8, 12, and 16 were found to be acetylated in a fraction of the histone IV molecules. Acetylation of each of these 4 lysyl residues can probably occur independently of the others, at least to some extent. This leads to a complex mixture of modified histone IV molecules, which is partially reflected in the starch gel pattern of this protein. There seems to be no acetylation of the other lysyl residues in the molecule.

Highlights

We report that all four of the lysyl residues 5, 8, 12, and 16 in histone IV from developing trout testis can be acetylated in viva, and evidence is presented which suggests that the four sites can be modified independently of one another, leading, in viva, to a complex mixture of partially acetylated histone IV molecules
Trod Testis-Testes were collected from naturally maturing rainbow trout (Salmo g&r&e&) during the months of October through December
The NHz-terminal of TAlb after removal of four amino acids was identified as glycine, and amino acid analysis of this residual peptide showed the presence of 1 residue each of glycine, alanine, lysine, and arginine (Table I, TAlb( -)4). This again confirms the identity of TAlb. These studies demonstrate that the 4 lysyl residues in the NHz-terminal region of histone IV are acetylated in viva in developing trout testis

Summary

SUMMARY

During the process of spermatogenesis in rainbow trout, there is extensive acetylation of some histone fractions. Acetylation of each of these 4 lysyl residues can probably occur independently of the others, at least to some extent This leads to a complex mixture of modified histone IV molecules, which is partially reflected in the starch gel pattern of this protein. Subsequent studies revealed that the major site of acetylation in calf thymus histones is not the NHz-terminal amino acid, but rather the E amino group of internal lysyl residues [3,4] ; this acetylation very likely takes place after synthesis of the histones [5]. We report that all four of the lysyl residues 5, 8, 12, and 16 in histone IV from developing trout testis can be acetylated in viva, and evidence is presented which suggests that the four sites can be modified independently of one another, leading, in viva, to a complex mixture of partially acetylated histone IV molecules

AND METHODS

AND DISCUSSION

Acetylation in Trout Testis Histone IV

TABLE I

GUY LySa GUY after Step in aqueous