Neural expression of a sodium channel gene requires cell-specific interactions.
In the protochordate Halocynthia roretzi, voltage-activated sodium current undergoes a change in kinetics within 48 hr of fertilization. Molecular cloning and microinjection of antisense DNA into single cells suggest that the kinetic changes are due to the increased expression of a putative neural-specific sodium channel gene, TuNa I. TuNa I gene transcription is first induced in late stage gastrulae, preceding the appearance of the rapidly inactivating sodium current unique to neural cells. In cleavage-arrested and intact embryos, cell interactions between specific animal and vegetal blastomeres are required for induction of TuNa I gene expression. Our results implicate cell contact, prior to neurulation, as a mechanism for selectively activating the TuNa I gene expressed in cells of the neural lineage.
Okamura
Y
Y
Department of Neurobiology, Faculty of Medicine, University of Tokyo, Japan.
Ono
F
F
Okagaki
R
R
Chong
J A
JA
Mandel
G
G
D000818:Animals; D001483:Base Sequence; D001757:Blastomeres / Q000166:cytology / Q000502:physiology; D002450:Cell Communication; D003001:Cloning, Molecular; D016373:DNA, Antisense / Q000494:pharmacology; D018076:DNA, Complementary / Q000737:chemistry; D015870:Gene Expression / Q000187:drug effects; D018014:Gene Transfer Techniques; D017403:In Situ Hybridization; D008845:Microinjections; D008969:Molecular Sequence Data; D009420:Nervous System / Q000196:embryology* / Q000254:growth & development / Q000378:metabolism; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000378:metabolism; D015222:Sodium Channels / Q000235:genetics* / Q000502:physiology; D014561:Urochordata / Q000196:embryology* / Q000254:growth & development / Q000378:metabolism
D016373:DNA, Antisense; D018076:DNA, Complementary; D012333:RNA, Messenger; D015222:Sodium Channels