Polysialic acid (polySia) is an oncofetal glycan that consists of 2,8-linked sialic acid monomers. This anionic homopolymer is best known as being synthesized on the glycoprotein neural cell adhesion molecule (NCAM). Biosynthesis of polySia in eukaryotes is performed by two polysialyltransferases (polySTs), St8Sia2 or St8Sia4, which are capable of synthesizing chain lengths estimated to contain up to 400 monomers. The interaction between the polyST and its NCAM acceptor, as well as the cellular functions of polySia, have been well-studied. However, how chain length and total polySia production is regulated is still poorly understood. In this dissertation, the hypothesis that changes in polyST expression levels can regulate polySia synthesis was investigated. To this end, a novel, cell-based system that allowed for tetracycline-inducible expression of either St8Sia2 or St8Sia4 in the same cell type was developed. As expected, polyST transcript levels directly correlated with polySia production. Interestingly, however, transcript levels within the range tested had no effect on the polysialylated NCAM glycoforms synthesized, determined by an assay that separated cell lysates using a low percentage polyacrylamide gel, followed by anti-polySia antibody Western blotting. Moreover, polysialylated NCAM glycoforms synthesized by St8Sia4-expressing cells showed a population that migrated slower than corresponding polysiaylated NCAM glycoforms synthesized by St8Sia2 expressing cells. This result is consistent with the conclusion that the two enzymes show an asymmetry in polySia production. Utilizing the inducible system, cell-matrix adherence assays revealed that increasing polySia expression on NCAM by both polySTs led to a decrease in cell adhesion to both fibronectin and laminin. When compared to cells expressing St8Sia4, St8Sia2-expressing cells resulted in a greater inhibition of cell adherence to laminin; however, these differences between the polySTs were not seen with the fibronectin binding. In conclusion, this inducible system of polyST and polySia has shown to be effective in studying how polyST transcript levels regulate polySia biosynthesis and function in regulating cell-matrix adherence. This system has revealed differences between St8Sia2 and St8Sia4 polysialylation of NCAM in vivo, as well as differential effects of cell adhesion to laminin, effects that have not been reported previously.