The aetiology of sperm protamine abnormalities and their potential impact on the sperm epigenome.
Int J Androl
; 31(6): 537-45, 2008 Dec.
Article
em En
| MEDLINE
| ID: mdl-18298569
ABSTRACT
During the elongating spermatid stage of spermatogenesis, there is a step-wise replacement of nuclear histones with protamines 1 and 2. In fertile men, the ratio of protamine 1/protamine 2 (P1/P2) is within the narrow range of 0.8-1.2. Ratios above or below that range are associated with infertility, exhibiting a wide range of defects including decreased sperm counts, morphology, fertilization ability, and embryo implantation capacity. In this review, we highlight studies evaluating potential causes of abnormal protamine expression, including the sequencing of genes relevant to protamine expression in both affected patients and controls. While the variants of the protamine genes themselves do not appear to be responsible for most observed defects, variants of the Contrin gene, a transcription factor and translation repressor, appear to be contributory to some cases of abnormal expression. Additionally, we explore the potential effects of abnormal protamine replacement on the epigenome of human sperm. Ongoing studies are evaluating the role of retained histones and DNA methylation in sperm, which may be affected in sperm with aberrant protamine replacement. This important area of epigenetic research has profound clinical implications.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Espermatogênese
/
Espermatozoides
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Protaminas
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Epigênese Genética
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Infertilidade Masculina
Limite:
Animals
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Humans
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Male
Idioma:
En
Revista:
Int J Androl
Ano de publicação:
2008
Tipo de documento:
Article
País de afiliação:
Estados Unidos