Kd. Fulcher et al., IDENTIFICATION OF A UNIQUE MU-CLASS GLUTATHIONE-S-TRANSFERASE IN MOUSE SPERMATOGENIC CELLS, Molecular reproduction and development, 42(4), 1995, pp. 415-424
The fibrous sheath is a major cytoskeletal structure in the principal
piece of the mammalian sperm flagellum. Two peptide sequences obtained
from a tryptic digest of mouse fibrous sheath proteins exhibited high
homology with mu-class glutathione S-transferases (GSTs). Using a DNA
probe amplified from degenerate polymerase chain reaction (PCR) prime
rs predicted from these two peptide sequences, a similar to 1.1 kb cDN
A clone for fibrous sheath component 2 (Fsc2) was isolated which had 8
4% nucleic acid and 89% amino acid sequence identity with a previously
reported mu-class human GST gene (hGSTM3; Campbell et al., 1990: J Bi
ol Chem 265:4188-9193). Sequences corresponding to those of the two fi
brous sheath peptides were present in the protein encoded by the Fsc2
cDNA. Northern analysis with the full length Fsc2 cDNA detected a simi
lar to 1.1 kb mRNA in 12 of 15 somatic tissues examined, as well as in
testis and isolated spermatogenic cells. However, 5'(nt -96 to 12) or
3' (nt 637 to 808) Fsc2 probes, containing mostly noncoding sequences
, detected a similar to 1.1 kb mRNA abundant in testis and isolated sp
ermatogenic cells, but absent or present at low levels in somatic tiss
ues. Northern analysis with RNA from testes of mice of different postn
atal ages and purified spermatogenic cell populations indicated that t
his transcript is first present during the meiotic phase of germ cell
development. These results suggest that a previously unreported mu-cla
ss GST gene (mGSTM5) is expressed at a specific time during the devel
opment of spermatogenic cells in the mouse. Immunoblot analysis indica
ted that a mu-class GST protein is associated with the fibrous sheath,
suggesting that it becomes an integral part of the mouse sperm cytosk
eleton. (C) 1995 Wiley-Liss, Inc.