Cellular vitamin A-binding proteins in the testis.
Vitamin A plays an important role in the testis, being essential for the maintenance of spermatogenesis. Studies on CRBP and CRABP suggest that both retinol and retinoic acid are involved in maintaining testicular function. The cellular location of the two proteins suggests that retinoic acid may be particularly involved in the later stages of germ cell differentiation, but retinol may be the form of vitamin A that the Sertoli cell receives initially. The requirement for vitamin A may be to regulate gene expression in the testis by direct interaction with the chromosomal material. Specific distinct binding sites for retinol and retinoic acid can be demonstrated in testicular nuclei and chromatin. These sites are only revealed when the two ligands are present in complex with their specific binding proteins, suggesting that these proteins may be required for the action of retinol and retinoic acid in some cells of the testis.
Ong
D E
DE
Departments of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232.
Takase
S
S
Chytil
F
F
D000818:Animals; D002352:Carrier Proteins / Q000502:physiology*; D002467:Cell Nucleus / Q000378:metabolism; D002843:Chromatin / Q000378:metabolism; D003593:Cytoplasm / Q000502:physiology; D008297:Male; D051381:Rats; D018168:Receptors, Retinoic Acid; D012177:Retinol-Binding Proteins / Q000502:physiology*; D054840:Retinol-Binding Proteins, Cellular; D013737:Testis / Q000502:physiology*; D014212:Tretinoin / Q000378:metabolism; D014801:Vitamin A / Q000378:metabolism / Q000502:physiology*
D002352:Carrier Proteins; D002843:Chromatin; D018168:Receptors, Retinoic Acid; D012177:Retinol-Binding Proteins; D054840:Retinol-Binding Proteins, Cellular; D014801:Vitamin A; D014212:Tretinoin