Transformation of ram spermatid chromatin

Loir, Maurice; Lanneau, M.

doi:10.1016/0014-4827(78)90277-x

Cited by 70 publications

(46 citation statements)

References 25 publications

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“…From the above results, which resemble those obtained with bulls, it seems that EDB, by its alkylating effect, disrupts the normal process of the replacement of the somatic by the sperm histones during the elongation phase of the spermatids (Loir and Lanneau, 1978), causing disorganization of the chromatin and contributing, indirectly, to the damage of the sperm DNA which remains, at least in part, dismantled from the protective sheath of its nucleoproteins.…”

Section: Ramssupporting

confidence: 75%

The spermicidal effect of ethylene dibromide in bulls and rams

Amir

1991

Molecular Reproduction Devel

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The spermicidal effect of ethylene dibromide (EDB) in bulls and rams is reviewed. Following oral or parenteral administration EDB was found to cause, by its alkylating effect in the testes of treated bulls and rams, lysis of the chromatin of the elongating spermatids during the time of somatin histones replacement by the sperm protamines. However, while in the bulls the abnormal spermatozoa issued from the affected spermatids were also collected in the ejaculates, this was not the case with treated rams. In the latter animals the abnormal spermatids seem to be phagocytized in the epididymis before their arrival in the ejaculate. In addition, whereas the alkylating effect of EDB occurred also in the upper parts of the epididymis of the bulls, causing tail and acrosome defects to the spermatozoa, in the rams such an effect seems to occur all along the epididymal duct. These differences between bulls and rams in the sites of the genital tract where the drug takes effect, and in the mechanism of this effect, reveal probable differences in the physiology of the reproductive tract between these species.

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Section: Ramssupporting

confidence: 75%

The spermicidal effect of ethylene dibromide in bulls and rams

Amir

1991

Molecular Reproduction Devel

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“…Electrophoretic and chromatographic analyses of these proteins have shown that the sperm of certain animals contain multiple protamine amino acid sequence variants and that the number of these variants differs from species to species. The sperm of bulls (24), rams (55,56), and rats (20,50), for example, contain only one protamine variant, whereas mouse sperm have two (6,9) and the sperm of humans (20,78) and certain fish (3) contain three different protamines.…”

mentioning

confidence: 99%

“…Concomitant with these visible changes in chromatin organization, the histone and nonhistone proteins are removed from the DNA and replaced for a period of time by several transition proteins . These proteins are subsequently replaced by protamine during the final stages of spermatid maturation, chromatin reorganization and condensation (11,12,14,35,36,48,56,61,71,76,78,85) .…”

mentioning

confidence: 99%

A model for the structure of chromatin in mammalian sperm.

Balhorn¹

1982

The Journal of Cell Biology

504

269

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DNA in mammalian, and most vertebrate sperm, is packaged by protamines into a highly condensed, biochemically inert form of chromatin. A model is proposed for the structure of this DNA-protamine complex which describes the site and mode of protamine binding to DNA and postulates, for the first time, specific inter- and intraprotamine interactions essential for the organization of this highly specialized chromatin. In this model, the central polyarginine segment of protamine binds in the minor groove of DNA, crosslinking and neutralizing the phosphodiester backbone of DNA while the COOH- and NH2-terminal ends of protamine participate in the formation of inter- and intraprotamine hydrogen, hydrophobic, and disulfide bonds. Each protamine segment is of sufficient length to fill one turn of DNA, and adjacent protamines are locked in place around DNA by multiple disulfide bridges. Such an arrangement generates a neutral, insoluble chromatin complex, uses all protamine sulfhydryl groups for cross linking, conserves volume, and effectively renders the chromatin invulnerable to most external influences.

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“…Like the cysteine-rich protamine of the sperm head (Grimes et al, 1977;Loir & Lanneau, 1978), these polypeptides are evidently synthesized in spermatids immediately before their assembly in sperm structures. The formation of dense fibres in the late stages of spermiogenesis over a prolonged period is indicated by morphological observations (Phillips, 1974;Clermont & Rambourg, 1978 (Calvin, 1979) (Setchell, 1978).…”

Section: Injection Of Tracersmentioning

confidence: 99%

Comparative labelling of rat epididymal spermatozoa by intratesticularly administered 65ZnCl2 and [35S]cysteine

Calvin¹

1981

Reproduction

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Transformation of ram spermatid chromatin

Cited by 70 publications

References 25 publications

The spermicidal effect of ethylene dibromide in bulls and rams

The spermicidal effect of ethylene dibromide in bulls and rams

A model for the structure of chromatin in mammalian sperm.

Comparative labelling of rat epididymal spermatozoa by intratesticularly administered 65ZnCl2 and [35S]cysteine

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