gamma-tubulin during the differentiation of spermatozoa in various mammalsand man

The distribution of gamma-tubulin as a marker of microtubule organizing cen tres (MTOC) was studied during spermiogenesis in rodents and in rabbit, mon key and man. A polyclonal antibody directed against human gamma-tubulin was used both for indirect immunofluorescence (IIF) and post-embedding immunog old procedures. In all species, gamma-tubulin was detected in the proximal and distal centrioles of round spermatids. In elongating spermatids, gamma- tubulin was predominantly found in the pericentriolar material (PCM) of bot h centrioles and particularly around the adjunct of the proximal centriole. At this level, some labelling was also associated with manchette microtubu les, but other parts of the manchette and the nuclear ring were never label led. We propose a role for distal centriole gamma-tubulin in axoneme nuclea tion and centriolar adjunct gamma-tubulin in manchette nucleation. The disa ppearance of gamma-tubulin in mature spermatozoa indicates that sperm aster nucleation should be dependent on oocyte gamma-tubulin. Remnants of gamma- tubulin in some human spermatozoa suggest that paternal gamma-tubulin also could contribute to sperm aster formation.