DIFFERENTIAL DISTRIBUTION OF GLUTAMYLATED TUBULIN IN THE FLAGELLUM OFMOUSE SPERMATOZOA

Using a monoclonal antibody (GT 335) we previously demonstrated that g lutamylation is a predominant posttranslational modification of alpha and beta tubulin isoforms in the axoneme of mouse spermatozoa (Fouquet et al., Cell Motil. Cytoskel. 27, 49, 1994). However, we noted that t he staining intensity and/or distribution of glutamylated tubulin were not identical using either indirect immunofluorescence (IIF) or immun oelectron microscopy. To test this discrepancy Various permeabilizatio n procedures were performed for IIF: methanol or acetone alone or in c ombination, including freezing pretreatment and with or without parafo rmaldehyde fixation. Each procedure gave a particular labeling of sper m axoneme. The diversity of axoneme labeling in mouse spermatids and s permatozoa appeared dependent both on the absence or presence of peria xonemal sheaths and permeabilization procedures. For comparison with I IF and to avoid problematic permeabilization treatments a quantitative postembedding immunogold approach was preferred. In these conditions the labeling predominated in the middle piece of the sperm flagellum a nd decreased progressively in the principal piece. However, the labeli ng of the terminal piece was similar to that of the middle piece. Thes e results suggested a differential glutamylated tubulin distribution a long the axoneme of the mouse sperm flagellum.