Isolation and characterization of the porcine proteolipid protein (PLP) gene

The proteolipid protein (PLP) is a highly conserved major membrane protein in the central nervous system (CNS). A series of neurological disorders caused by mutations in the X-chromosomal PLP gene were described among mammals comprising jimpy in mouse, Pelizaeus-Merzbacher Disease and Spastic Paraplegia type 2 in humans, shaking pup in dop, and paralytic tremor in rabbit. These disorders share common features comprising tremor, nystagmus, ataxia, and a high degree of lethality. The X-linked porcine congenital tremor type A III (CT AIII) shows a high degree of similarity on the morphologic and cellular level to these PLP-linked disorders. Affected piglets suffer from cramps, vertical and lateral shaking of the head and rump as well as spontaneous limb movement. The axons in brain and spinal cord are only loosely enwrapped and the number of of oligodendrocytes is decreased. Due to these similarities we propose the involvement of PLP in establishment of CT AIII which has never been investigated on the molecular level. This study describes the isolation and partial characterization of the porcine PLP at the transcriptional and genomic level.