Identification of Kv1.1 expression by murine CD4-CD8- thymocytes. A role for voltage-dependent K+ channels in murine thymocyte development.
The patch-clamp recording technique and RNA-polymerase chain reaction were used to identify the voltage-dependent K+ channels expressed by murine fetal and adult CD4-CD8- thymocytes. Two distinct currents, encoded by the genes Kv1.1 and Kv1.3 were identified based upon their biophysical and pharmacologic characteristics and confirmed with RNA-polymerase chain reaction. Peptide blockers of Kv1.1 and Kv1.3 gene products were also applied to a murine fetal thymic organ culture system to investigate the developmental role of these K+ channels. Dendrotoxin (DTX) and charybdotoxin (CTX), antagonists of Kv1.1 and Kv1.3 channels, respectively, decreased thymocyte yields in organ culture without affecting thymocyte viability. DTX-treated thymi contained 56 +/- 8% (n = 8 experiments), and CTX-treated thymi contained 74 +/- 4% (n = 7 experiments) as many thymocytes as untreated lobes. DTX and CTX also altered the developmental progression of thymocytes in fetal organ culture. These data provide the first evidence of Kv1.1 expression in a lymphoid cell and indicate that thymocyte voltage-dependent K+ channels are critical to thymocyte preclonal expansion and/or maturation.
Freedman
B D
BD
Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia 19104, USA.
Fleischmann
B K
BK
Punt
J A
JA
Gaulton
G
G
Hashimoto
Y
Y
Kotlikoff
M I
MI
D000818:Animals; D001483:Base Sequence; D002455:Cell Division / Q000187:drug effects; D017931:DNA Primers / Q000737:chemistry; D004546:Elapid Venoms / Q000494:pharmacology; D005260:Female; D015870:Gene Expression; D008297:Male; D008564:Membrane Potentials; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D009924:Organ Culture Techniques; D011188:Potassium / Q000502:physiology; D015221:Potassium Channels / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D012604:Scorpion Venoms / Q000494:pharmacology; D016176:T-Lymphocyte Subsets / Q000166:cytology / Q000378:metabolism*; D013950:Thymus Gland / Q000166:cytology / Q000196:embryology*
D017931:DNA Primers; D004546:Elapid Venoms; D015221:Potassium Channels; D012333:RNA, Messenger; D012604:Scorpion Venoms; C072276:kaliotoxin; C020273:dendrotoxin; D011188:Potassium