Expression of microtubule-associated protein-2a and other novel microtubule-associated protein-2 transcripts in human fetal spinal cord.
In human fetal spinal cord (HFSC), six additional microtubule-associated protein-2 (MAP-2) transcripts are generated by alternative splicing of two recently described exons, exon 8 and exon 13. The following three translated proteins are detected by western blot analysis: MAP-2b expressing exon 8 (MAP-2b + 8; MAP-2a), MAP-2b expressing exon 13 (MAP-2b + 13), and MAP-2c expressing exon 8 and exon 13 (MAP-2c + 8 + 13). The finding that MAP-2b + 8 is expressed in HFSC demonstrates for the first time the presence of MAP-2a in human fetal CNS. Immunocytochemical studies show that exon 8-specific antibody and exon 13-specific antibody stain independent and overlapping populations of neurons in the lumbar region of the HFSC. Antibody 13-immunopositive neurons have predominantly cytosolic staining, whereas in the antibody 8-immunoreactive neurons staining was observed in the cytosol, dendrites, and some synapses. The prenatal expression of MAP-2a, which has been used as a marker of synaptogenesis, not only demonstrates the presence of a mature MAP-2 isoform in HFSC, but suggests that MAP-2a is important during human fetal as well as postnatal synaptogenesis.
Kalcheva
N
N
Department of Pathology (Neuropathology), Albert Einstein College of Medicine, Bronx, New York 10461, USA.
Weidenheim
K M
KM
Kress
Y
Y
Shafit-Zagardo
B
B
D005314:Embryonic and Fetal Development; D005091:Exons; D005333:Fetus / Q000378:metabolism* / Q000648:ultrastructure; D006801:Humans; D008161:Lumbosacral Region; D008869:Microtubule-Associated Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D008970:Molecular Weight; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000378:metabolism*; D013116:Spinal Cord / Q000196:embryology* / Q000378:metabolism / Q000648:ultrastructure; D013569:Synapses / Q000648:ultrastructure; D014158:Transcription, Genetic
D008869:Microtubule-Associated Proteins; D012333:RNA, Messenger