Rodler, Daniela; Sinowatz, Fred
Expression of Intermediate Filaments in the Balbiani Body and Ovarian Follicular Wall of the Japanese Quail (Coturnix japonica).
In: Cells Tissues Organs, No. 4: pp. 298-311
In the present study, we examined the distribution of 6 groups ofintermediate filaments (IFs; cytokeratins, CKs, vimentin, synemin,desmin, glial fibrillary acidic protein and lamins) in oocytes andfollicular walls of the Japanese quail (Coturnix japonica) during theirdevelopment using immunohistochemical and ultrastructural techniques. Adistinctly vimentin- and synemin-positive Balbiani body, which is atransient accumulation of organelles (mitochondria, Golgi complex andendoplasnnic reticulum) that occurs in the oocytes of all vertebratesincluding birds, could be detected in the oocytes of primordial andearly pre-vitellogenic follicles. In larger pre-vitellogenic follicles,the Balbiani body has dispersed and the positivity of the granulosacells appeared to concentrate in the basal portion of their cytoplasm.Our ultrastructural data demonstrated that the matrix of the Balbianibody consists of fine IFs, which may play a role in the formation anddispersion of the Balbiani body. Of the CKs studied (panCK, CK5, CK7,CK8, CK14, CK15, CK18 and CK19), only CK5 showed a slight positivestaining in both the theca externa and the Balbiani bodies ofpre-vitellogenic oocytes. In conclusion, our data, which describe thechanges in avian IF protein expression during folliculogenesis, suggestthat the functions of the IFs (vimentin and synemin) of oocytes andfollicular walls are not primarily mechanical but may be involved in thetransient tethering of mitochondria in the area of the Balbiani body andin the gain of endocrine competence during the differentiation ofgranulosa cells.