Expression of glycogen synthase kinase-3 isoforms in mouse tissues and their transcription in the brain.
Glycogen synthase kinase-3alpha and -3beta (GSK-3alpha and -3beta) are multi-substrate, serine/threonine-specific kinases that can phosphorylate microtubule-associated protein tau and other neuronal proteins. In this study, the expression level and mRNA distribution of two GSK-3 isoforms, GSK-3alpha and -3beta in mice were investigated. Northern blot analyses indicated that GSK-3alpha mRNA is encoded by a 2.5-kb transcript in adult tissues, whereas a 4.1-kb transcript was found in neonatal tissues. The GSK-3beta mRNA is encoded by a 1.6-kb transcript in the testis and a 7.6-kb transcript in the brain, and in many other adult tissues, but not neonatal tissues. Western blot analyses demonstrated that GSK-3beta protein was mainly expressed in the brain and heart, whereas GSK-3alpha was highly expressed in the brain, heart, and testis. A non-radioactive in situ hybridization study using specific digoxigenin-labeled RNA probes showed that GSK-3alpha and -3beta mRNAs were found in many brain regions, and were especially abundant in the hippocampus, cerebral cortex, and the Purkinje cells of the cerebellum. This implies the importance of GSK-3alpha and -3beta for brain function. The differential expression of GSK-3alpha and -3beta mRNAs as well as proteins in other tissues indicate that they play different roles in cellular functions and the developmental process.
Yao
Hong-Bing
HB
Department of Biochemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China.
Shaw
Pang-Chui
PC
Wong
Chun-Cheung
CC
Wan
David Chi-Cheong
DC
D000595:Amino Acid Sequence; D000818:Animals; D000831:Animals, Newborn; D001921:Brain / Q000201:enzymology* / Q000502:physiology; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000096:biosynthesis*; D018507:Gene Expression Regulation, Developmental / Q000502:physiology; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology; D038362:Glycogen Synthase Kinase 3; D038341:Glycogen Synthase Kinases; D007527:Isoenzymes / Q000096:biosynthesis; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000096:biosynthesis; D014158:Transcription, Genetic / Q000502:physiology*
D007527:Isoenzymes; D012333:RNA, Messenger; D038341:Glycogen Synthase Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D038362:Glycogen Synthase Kinase 3