title: Expression patterns in alternative splicing forms of prosaposin mRNA in the rat facial nerve nucleus after facial nerve transection.
abstract: Prosaposin acts as a neurotrophic factor, in addition to its role as the precursor protein for saposins A, B, C, and D, which are activators for specific sphingolipid hydrolases in lysosomes. In rats, the prosaposin gene generates two alternative splicing forms of mRNA: Pro+9 containing a 9-base insertion and Pro+0 without. The expression of these mRNAs changes after brain injury. We examined the expression patterns of the alternative splicing forms of prosaposin mRNA in the rat facial nerve nucleus for 52 days following facial nerve transection. Pro+0 mRNA increased within 3 days of transection, peaked after 5-10 days, and remained significantly elevated for 21 days. In contrast, the expression of Pro+9 mRNA was constant throughout the regenerative period. Prosaposin mRNA expression increased not only in facial motoneurons, but also in microglia during facial nerve regeneration. Our findings indicate that the saposin B domain of prosaposin, which is the domain affected by alternative splicing, plays an important role in both neurons and microglia during neuroregeneration.
authors.affiliation: Division of Anatomy and Embryology, Department of Integrated Basic Medical Science, Ehime University School of Medicine, Shitsukawa, To-on, Ehime 791-0295, Japan.
authors.forename: Jie
authors.initials: J
authors.lastname: Chen
authors.forename: Shouichiro
authors.initials: S
authors.lastname: Saito
authors.forename: Naoto
authors.initials: N
authors.lastname: Kobayashi
authors.forename: Kohji
authors.initials: K
authors.lastname: Sato
authors.forename: Takehiro
authors.initials: T
authors.lastname: Terashita
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Shimokawa
authors.forename: Katsumi
authors.initials: K
authors.lastname: Mominoki
authors.forename: Kyojy
authors.initials: K
authors.lastname: Miyawaki
authors.forename: Akira
authors.initials: A
authors.lastname: Sano
authors.forename: Seiji
authors.initials: S
authors.lastname: Matsuda
mesh_terms: D017398:Alternative Splicing / Q000235:genetics*; D000818:Animals; D003714:Denervation; D005154:Facial Nerve / Q000378:metabolism* / Q000503:physiopathology; D020220:Facial Nerve Injuries / Q000235:genetics / Q000378:metabolism* / Q000503:physiopathology; D005786:Gene Expression Regulation / Q000502:physiology; D008297:Male; D017628:Microglia / Q000378:metabolism; D009046:Motor Neurons / Q000378:metabolism*; D009416:Nerve Regeneration / Q000235:genetics; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary / Q000502:physiology; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D020127:Recovery of Function / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012249:Rhombencephalon / Q000378:metabolism* / Q000503:physiopathology; D049231:Saposins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics*; D015854:Up-Regulation / Q000235:genetics
chemical_list: D020033:Protein Isoforms; C483347:Psap protein, rat; D012333:RNA, Messenger; D049231:Saposins