Conservation and expression of IQ-domain-containing calpacitin gene products (neuromodulin/GAP-43, neurogranin/RC3) in the adult and developing oscine song control system.
Songbirds are appreciated for the insights they provide into regulated neural plasticity. Here, we describe the comparative analysis and brain expression of two gene sequences encoding probable regulators of synaptic plasticity in songbirds: neuromodulin (GAP-43) and neurogranin (RC3). Both are members of the calpacitin family and share a distinctive conserved core domain that mediates interactions between calcium, calmodulin, and protein kinase C signaling pathways. Comparative sequence analysis is consistent with known phylogenetic relationships, with songbirds most closely related to chicken and progressively more distant from mammals and fish. The C-terminus of neurogranin is different in birds and mammals, and antibodies to the protein reveal high expression in adult zebra finches in cerebellar Purkinje cells, which has not been observed in other species. RNAs for both proteins are generally abundant in the telencephalon yet markedly reduced in certain nuclei of the song control system in adult canaries and zebra finches: neuromodulin RNA is very low in RA and HVC (relative to the surrounding pallial areas), whereas neurogranin RNA is conspicuously low in Area X (relative to surrounding striatum). In both cases, this selective downregulation develops in the zebra finch during the juvenile song learning period, 25-45 days after hatching. These results suggest molecular parallels to the robust stability of the adult avian song control circuit.
Clayton
David F
DF
Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Illinois 61801, USA. dclayton@uiuc.edu
George
Julia M
JM
Mello
Claudio V
CV
Siepka
Sandra M
SM
D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D003001:Cloning, Molecular; D046369:Finches; D019922:GAP-43 Protein / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D053400:High Vocal Center / Q000254:growth & development* / Q000378:metabolism*; D042541:Intracellular Space / Q000378:metabolism; D051579:Neurogranin / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D017421:Sequence Analysis; D014828:Vocalization, Animal / Q000502:physiology*
D019922:GAP-43 Protein; D012333:RNA, Messenger; D051579:Neurogranin