of the Max - MDC

Structure of the Group
Group Leader
Dr. Ines Ibanez-Tallon
Scientists
Dr. Silke Frahm
Dr. Beate Liehl*
Dr. Julio Santos-Torres
Graduate Students
Annika Stürzebecher
Martin Laqua
Sebastian Auer
Marta Slimek
Technical Assistant
Branka Kampfrath
Secretariat
Annette Schledz
* part of the period reported
A
B
(A) Scheme of a transmembrane tethered toxin. The toxin binding to the
pore of the channel is attached to the cell membrane via a transmembrane
domain fused to EGFP at the cytoplasmic side. (B) Transduction of neuronal
cultures with lentivirus carrying TM-toxins show EGFP and FLAG immunoreactivity
at the neuronal membrane. (C) Functional test in xenopus oocytes
indicate that tethered toxins maintain their blocking capability.
C
abnormal high frequency. We have generated BAC transgenic
mice that selectively express a tethered toxin against
TTX-R sodium and calcium voltage channels in nociceptive
DRG neurons. These mice are being evaluated by electrophysiology,
skin-nerve assays and pain behavioral tests in
collaboration with the group of Gary Lewin at the MDC.
Development of optimized inducible tethered
toxins for neuronal silencing
Sebastian Auer, Beate Liehl*
To better monitor the expression of the tethered toxins in
vivo and to access to other types of voltage-gated channels,
we have cloned and optimized a number of peptide toxins in
tethered isoforms fused to transmembrane domains followed
by EGFP and Cherry fluorescent reporters. In particular,
several newly identified peptide toxins and mutant variants
in their tethered form are being screened as suitable
candidates to block TTX-S channels which are at the base of
neuronal transmission in the central nervous system. These
are tested electrophysiologically in Xenopus oocytes and in
neuronal cultures or brain slices transduced with inducible lentiviral
vectors. The development of broad range and specific tethered
toxins against these channels that can be expressed at high levels
and in an inducible on/off manner will have enormous applications
to the study of functional circuits.
Selected Publications
Ibañez-Tallon I., Miwa J.M., Wang H-L., Adams N.C., Crabtree
G.W., Sine S.M. and Heintz N. (2002). Novel modulation of neuronal
nicotinic acetylcholine receptors by direct association with
the endogenous prototoxin lynx1. Neuron, 33, 893-903.
Ibañez-Tallon I., Gorokhova S. and Heintz N. (2002) Loss of
function of axonemal dynein Mdnah5 causes primary ciliary
dyskinesia and hydrocephalus. Human Molecular Genetics, 11,
715-721.
Ibañez-Tallon I., Pagenstecher A., Fliegau M., Olbrich H., Kispert
A., Ketelsen U-P., North A.J., Heintz N. and Omran H. (2004).
Axonemal dynein deficiency for Mdnah5 reveals a novel mechanism
for hydrocephalus formation. Human Molecular Genetics,
13(18):2133-2141.
Ibañez-Tallon, I., Wen H., Miwa J., Xing J., Ono F., Brehm, P.
and Heintz. N. (2004) Tethering naturally occurring peptides for
cell autonomous manipulation of receptors and ion channels in
vivo. Neuron, 43(3):305-311.
Miwa J.M., King S. L., Stevens T. R., Caldarone B. J. , Ibañez-
Tallon, I, Fitzsimonds R. M., Pavlides C., Picciotto M.R., Heintz
N. (2006). Balancing neuronal activity and survival via the cholinergic
modulator lynx1. Neuron, 51(5):587-600.
Hruska M., Ibañez-Tallon I., Nishi R. (2007) Cell autonomous
inhibition ofalpha7-containing nicotinic acetylcholine receptors
prevents death of parasympathetic neurons during development.
J. Neurosci. 27: 11501-11509.
180 Function and Dysfunction of the Nervous System