The Loss of Polysialic Acid Impairs the Contractile Phenotype of Peritubular Smooth Muscle Cells in the Postnatal Testis.

In the testis, the germinal epithelium of seminiferous tubules is surrounded by contractile peritubular cells, which are involved in sperm transport. Interestingly, in postnatal testis, polysialic acid (polySia), which is also an essential player for the development of the brain, was observed around the tubules. Western blotting revealed a massive decrease of polySia from postnatal day 1 towards puberty, together with a fundamental reduction of the net-like intertubular polySia.

Polysialylation takes place in granulosa cells during apoptotic processes of atretic tertiary follicles.

In the neuronal system, polysialic acid (polySia) is known to be involved in several cellular processes such as the modulation of cell-cell interactions. This highly negatively-charged sugar moiety is mainly present as a post-translational modification of the neural cell adhesion molecule (NCAM). More than 20 years ago, differently glycosylated forms of NCAM were detected in the ovaries.

Polysialylation of NCAM characterizes the proliferation period of contractile elements during postnatal development of the epididymis.

Polysialic acid (polySia) attached to the neural cell adhesion molecule (NCAM) regulates inter alia the proliferation and differentiation via the interactions with neurotrophins. Since in postnatal epididymis neurotrophins and their receptors like the Low-Affinity Nerve Growth Factor Receptor p75 and TrK B receptor are expressed, we wanted to analyze if the polysialylation of NCAM is also involved during the development of the epididymis. To this end, we monitored the developmental changes in the expression of the polysialyltransferases and NCAM polysialylation using murine epididymis at different time points during postnatal development.

Polysialylation of NCAM correlates with onset and termination of seasonal spermatogenesis in roe deer.

Roe deer (Capreolus capreolus) are seasonal breeders and cyclic structural changes of roe bucks' testis come along with a totally arrested (winter) and a highly activated spermatogenesis (summer). For this reason, roe buck represents an interesting model to study general mechanisms of initiation and termination of spermatogenesis. We investigated if polysialic acid (polySia)-a linear homopolymer of α2,8-linked sialic acids, which could act as a negative regulator of cell-cell adhesion-might be involved in the activation and/or inactivation of spermatogenesis.

Polysialic acid is present in mammalian semen as a post-translational modification of the neural cell adhesion molecule NCAM and the polysialyltransferase ST8SiaII.

Fertilization in animals is a complex sequence of several biochemical events beginning with the insemination into the female reproductive tract and, finally, leading to embryogenesis. Studies by Kitajima and co-workers (Miyata, S., Sato, C.