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Vertebrate reproductive science and technology
RESEARCH ARTICLE

Relocation of myosin and actin, kinesin and tubulin in the acrosome reaction of bovine spermatozoa

Ifigenia Oikonomopoulou A B , Hitesh Patel A , Paul F. Watson A and Peter D. Chantler A B
+ Author Affiliations
- Author Affiliations

A Royal Veterinary College, Royal College Street, London NW1 0TU, UK.

B Present address: Institute for Stem Cell Research, University of Edinburgh, Edinburgh EH9 3JQ, UK.

C Corresponding author. Email: pchant@rvc.ac.uk

Reproduction, Fertility and Development 21(2) 364-377 https://doi.org/10.1071/RD08166
Submitted: 30 July 2008  Accepted: 22 September 2008   Published: 27 January 2009

Abstract

The mammalian acrosome reaction is a specialised exocytotic event. Although molecular motors are known to be involved in exocytosis in many cell types, their potential involvement in the acrosome reaction has remained unknown. Here, it has been shown that actin is localised within the equatorial segment and in the marginal acrosomal ridge of the heads of unreacted bull spermatozoa. Myosins IIA and IIB are found within the anterior acrosomal margins of virtually all sperm cells and, less prominently, within the equatorial segment. Tubulin was detected in the equatorial segment and around the periphery of the acrosome while kinesin was prominent in the equatorial segment. After induction of the acrosome reaction by means of the calcium ionophore A23187, the number of cells exhibiting actin fluorescence intensity in the anterior acrosomal margin decreased four-fold and those displaying equatorial segment fluorescence decreased 3.5-fold; myosin IIA immunofluorescence decreased in intensity with most spermatozoa losing equatorial staining, whereas there was little change in the distribution or intensity of myosin IIB immunofluorescence, except for a ~20% decrease in the number of cells exhibiting acrosomal staining. Tubulin became largely undetectable within the head and kinesin staining spread rostrally over the main acrosome region. A possible sequence of events that ties in these observations of molecular motor involvement with the known participation of SNARE proteins is provided.

Additional keywords: acrosomal membrane, membrane fusion, molecular motors, plasma membrane.


Acknowledgements

We thank the Research Department and the Department of Veterinary Basic Sciences of the Royal Veterinary College for their support and provision of facilities. We also thank Helen Smith for advice on confocal microscopy and Brian Cox and Jack Sisterson for assistance with figure preparation. We have no conflict of interest to declare.


References

Abou-Haila, A. , and Tulsiani, D. R. (2000). Mammalian sperm acrosome: formation, contents, and function. Arch. Biochem. Biophys. 379, 173–182.
Crossref | GoogleScholarGoogle Scholar | PubMed | CAS | Yanagimachi R. (1994). Mammalian fertilization. In ‘The Physiology of Reproduction’. 2nd edn. (Eds E. Knobil and J. D. Neill.) pp.189–317. (Raven Press: New York.)

Yang, W. X. , and Sperry, A. O. (2003). C-terminal kinesin motor KIFC1 participates in acrosome biogenesis and vesicle transport. Biol. Reprod. 69, 1719–1729.
Crossref | GoogleScholarGoogle Scholar | PubMed | CAS |