Open AccessIsolation and characterization of a small putative zinc finger protein from cuttlefish epididymal sperm cells
Author(s) -
MARTINPONTHIEU Annie,
WOUTERSTYROU Danièle,
PUDLO Barbara,
BUISINE Eric,
SAUTIÈRE Pierre
Publication year - 1994
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1994.tb18644.x
Subject(s) - protamine , zinc finger , biology , spermatid , sperm , spermiogenesis , nuclear protein , biochemistry , cysteine , sp1 transcription factor , chromatin , microbiology and biotechnology , genetics , gene , transcription factor , gene expression , heparin , enzyme , promoter
At the end of spermiogenesis, sperm chromatin stabilization is ensured by protamine dephosphorylation and, in mammals, by the formation during epididymal transit, of intra‐ and inter‐molecular disulfide bridges between protamines. In cuttlefish, the nuclear protein transition histones → spermtid‐specific protein T→protamine Sp is very similar to that occurring in mammals during spermiogenesis. However, in cuttlefish, the protamine Sp is devoid of cysteine residues. The protein complement of cuttlefish epididymal sperm nuclei has been investigated. A minor basic protein, called protein E, has been isolated. Its primary structure was established from sequence analysis and mass spectrometry data of the protein and its fragments. Protein E contains a motif ‐Cys‐Xaa 2 ‐Cys‐Xaa 23 ‐His‐Cys‐Xaa 2 ‐Cys‐ which is likely to adopt a zinc finger conformation. Reduced protein E does fix zinc whereas alkylation of cysteine residues abolishes this ability. The sequence of protein E does not correspond to that of any known protein, but presents some similarities with a part of ZFY protein, a putative human transcription factor specifically expressed in germinal cells and which could be involved in spermatogenesis.