Aim: To study the localization of CTP: phosphocholine cytidylyltransferase beta isoform (CCTbeta) in rat brain, its expression in insect cells and enzymatic properties.
Methods: Using digoxigenin-labeled CCTbeta probes, in situ hybridization was carried out in rat brain wax sections. CCTbeta was overexpressed in Trichoplusia Ni (Tn) cells using baculovirus expression system. CTP:phosphocholine cytidylyltransferase assay (CT assay) and [3H] metabolic labeling experiment were used to study its activity, properties, and the effect on phosphatidylcholine (PC) synthesis.
Results: (1) CCbeta was abundant in CA1, CA2, CA4, and dentate gyrus (DG) region of hippocampus. (2) The content of CCTbeta in transfected Tn cells was over 1 104 times of that in rat brain, and CCTbeta increased the PC synthesis of Tn cells. (3) Hexadecylphosphocholine as well as some ions like Zn2+ and PO3-4 could inhibit the activity of CCTbeta, dCTP was another adaptive substrate of CCTbeta besides CTP.
Conclusion: CCTbeta showed a similar localization in rat brain with the memory enhancing peptide argipressin (4-8).