Changes of γ-tubulin expression and distribution in the zebrafish (Danio rerio) ovary, oocyte and embryo

The tubulin gene family is important for individual zebrafish development from the oocyte through to hatching. This involves often rapid, complex changes in the gametes and embryonic cells that are reflected in underlying gene expression changes. Tubulin dynamics, i.e., the interchange of polymeric and soluble forms in zebrafish oogenesis and embryogenesis, is important for microtubule (MT) cellular functions. Nevertheless, our understanding of how tubulin gene expression changes during zebrafish development is not clear. Previous data showed that soluble α-tubulin and γ-tubulin are associated with large molecular weight complexes (>2 MDa) which are reduced by the blastula stage, with a concomitant decrease in soluble tubulin amount. Complexes (<2 MDa) then increased in the gastrula with an increase in soluble tubulin. Microarray revealed similar patterns of tubulin gene product expression for zebrafish ovary and eggs while both differed from day 4 larva. In situ hybridization with γ-tubulin oligonucleotide probes revealed diffuse label in oocytes, with a marked localization to the primordial blastodisc upon maturation. These findings, together with recent work on γ-tubulin ring complexes in other species, suggest that γ-tubulin (protein complexes) may be involved in regulating tubulin dynamics, thus is important for zebrafish oogenesis and embryogenesis.