Early socio-emotional experience induces expression of the immediate-early gene Arc/arg3.1 (activity-regulated cytoskeleton-associated protein/activity-regulated gene) in learning-relevant brain regions of the newborn chick.
We have cloned a full-length complementary DNA from the chicken (Gallus gallus domesticus), which encodes a polypeptide that exhibits approximately 75% identity to the product of the mammalian gene Arc (activity-regulated cytoskeleton-associated protein), also known as arg3.1 (activity-regulated gene). Since this gene is an immediate-early gene that has been suggested to play a role in synaptic plasticity and learning and memory processes, its expression has been analyzed in a juvenile form of learning, namely, filial imprinting. Our results demonstrate that Arc/arg3.1 mRNA is detectable in the newborn chick brain, and that at this early age the level of this transcript can be altered by brief sensory/emotional experience. After postnatal exposure to a novel 30-min auditory imprinting stimulus, Arc/arg3.1 mRNA was found to be significantly increased in two higher associative areas, the mesopallium intermediomediale (P = 0.002) and the nidopallium dorso-caudale (P = 0.031), compared with naïve controls. The transcript level was also significantly elevated after imprinting in Area L pallii (P=0.045), which is analogous to the mammalian auditory cortex. In addition, increases were seen in the medio-rostral nidopallium/mesopallium (P = 0.054), which is presumed to be the analog of the mammalian prefrontal cortex, and the hyperpallium intercalatum (P = 0.054), but these did not quite reach significance. We discuss these data in the light of those obtained in an earlier study, in the same paradigm, for the avian immediate-early gene, zenk (an acronym for zif-268, egr-1, ngfi-a and krox-24, which are different names for the orthologous mammalian gene). We conclude that, although both the Arc/arg3.1 and zenk genes are induced by auditory imprinting, they are significantly up-regulated in different learning-relevant brain regions. It is, therefore, evident that they must be activated by different mechanisms.
Bock
J
J
Institut für Biologie, Otto-von-Guericke Universität, Brenneckestrasse 6, 39118 Magdeburg, Germany.
Thode
C
C
Hannemann
O
O
Braun
K
K
Darlison
M G
MG
D000161:Acoustic Stimulation; D000595:Amino Acid Sequence; D000818:Animals; D000831:Animals, Newborn; D001245:Association Learning / Q000502:physiology; D001921:Brain / Q000254:growth & development / Q000502:physiology*; D002645:Chickens; D003598:Cytoskeletal Proteins / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics; D051766:Early Growth Response Protein 1; D018507:Gene Expression Regulation, Developmental; D015723:Gene Library; D017781:Genes, Immediate-Early / Q000502:physiology; D017874:Immediate-Early Proteins / Q000235:genetics; D007173:Imprinting, Psychological / Q000502:physiology*; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000235:genetics*; D009473:Neuronal Plasticity / Q000502:physiology; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D012919:Social Behavior; D014157:Transcription Factors / Q000235:genetics
D003598:Cytoskeletal Proteins; D004268:DNA-Binding Proteins; D051766:Early Growth Response Protein 1; D017874:Immediate-Early Proteins; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; D014157:Transcription Factors; C092069:activity regulated cytoskeletal-associated protein