Cloning and expression of three K+ channel cDNAs from Xenopus muscle

Fry, Mark; Paterno, Gary D.; Moody-Corbett, F

doi:10.1016/s0169-328x(01)00096-1

Cited by 6 publications

(7 citation statements)

References 52 publications

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“…Kv genes expressed in the embryonic Xenopus spinal cord include Kv1.1, Kv1.2, Kv1.4, Kv1.10, Kv2.2, Kv3.1, Kv␤4, and Kv␤2 (Ribera and Nguyen, 1993;Burger and Ribera, 1996;Lazaroff et al, 1999;Gurantz et al, 2000;Fry et al, 2001). Interestingly, the expression patterns of the majority of these genes show regional differences along the dorsal-ventral axis.…”

Section: Discussionmentioning

confidence: 99%

Dorsal–Ventral Gradient for Neuronal Plasticity in the Embryonic Spinal Cord

Pineda

Ribera²

2008

J. Neurosci.

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Within the developing Xenopus spinal cord, voltage-gated potassium (Kv) channel genes display different expression patterns, many of which occur in opposing dorsal-ventral gradients. Regional differences in Kv gene expression would predict different patterns of potassium current (I Kv ) regulation. However, during the first 24 h of postmitotic differentiation, all primary spinal neurons undergo a temporally coordinated upregulation of I Kv density that shortens the duration of the action potential. Here, we tested whether spinal neurons demonstrate regional differences in I Kv regulation subsequent to action potential maturation. We show that two types of neurons, I and II, can be identified in culture on the basis of biophysical and pharmacological properties of I Kv and different firing patterns. Chronic increases in extracellular potassium, a signature of high neuronal activity, do not alter excitability properties of either neuron type. However, elevating extracellular potassium acutely after the period of action potential maturation leads to different changes in membrane properties of the two types of neurons. I Kv of type I neurons gains sensitivity to the blocker XE991, whereas type II neurons increase I Kv density and fire fewer action potentials. Moreover, by recording from neurons in vivo, we found that primary spinal neurons can be identified as either type I or type II. Type I neurons predominate in dorsal regions, whereas type II neurons localize to ventral regions. The findings reveal a dorsal-ventral gradient for I Kv regulation and a novel form of neuronal plasticity in spinal cord neurons.

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Section: Discussionmentioning

confidence: 99%

Dorsal–Ventral Gradient for Neuronal Plasticity in the Embryonic Spinal Cord

Pineda

Ribera²

2008

J. Neurosci.

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“…The open reading frames of XKv1.2, XKv1.4, and XKv1.10 cDNAs were amplified from embryonic Xenopus skeletal muscle cDNA using the polymerase chain reaction, as previously described (Fry et al, 2001). The PCR products were initially subcloned into the pCR2.1 vector (Invitrogen, Carlsbad, CA), then excised and subcloned into the pCDNA3 expression vector (Invitrogen).…”

Section: Methods Cdna Clonesmentioning

confidence: 99%

“…While we recently reported the expression of a novel K ϩ channel gene (XKv1.10) in excitable tissue of developing Xenopus laevis (Fry et al, 2001), the biophysical properties of this isoform were unknown. Whole cell patch clamp recording from HEK293 cells expressing XKv1.10 K ϩ channel cDNA revealed K ϩ currents, which rapidly activated and incompletely inactivated in response to depolarizing voltage pulses ( Fig.…”

Section: Biophysical Properties Of Xkv110mentioning

confidence: 99%

“…Furthermore, the appearance of XKv1.10 transcripts in Xenopus spinal cord coincides with the time when action potential duration shortens in developing spinal cord neurons in culture (Barish, 1986;O'Dowd et al, 1988;Ribera and Spitzer, 1990), and the potential of half-inactivation (Ϫ37.8 mV) for XKv1.10 is similar to the Ϫ40 mV reported for I KA in spinal cord neurons in culture (Ribera and Spitzer, 1990), suggesting that XKv1.10 may contribute to I KA . Importantly, however, XKv1.10 may also form heteromultimers with other subunits, including XKv1.4 (Fry et al, 2001;Kerschbaum et al, 2002) and/or ␤ subunits (Lazaroff et al, 1999), and in this way contribute to I KA and/or I IK .…”

Section: Currents Observed In Excitable Cells Of Embryonic Xenopusmentioning

confidence: 99%

“…Of these, homologues of Kv 1.1, Kv1.2, Kv1.4, Kv1.10, Kv2.1, Kv2.2, Kv3.1 KvLQT1 (Ribera, 1990;Ribera and Nguyen, 1993;Burger and Ribera, 1996;Sanguinetti et al, 1996;Gurantz et al, 2000;Fry et al, 2001;Kerschbaum et al, 2002), Kv4.3 (Lautermilch and Spitzer, unpublished clone accession #U89265), and SLO (Kukuljan et al, unpublished clone accession #AF274053) have been isolated from Xenopus. While the biophysical properties of some of these channels have been examined, the functional properties of the novel Kv1 subfamily member XKv1.10 (Fry et al, 2001) have not been reported. Therefore, the purpose of this study was to examine the biophysical properties of XKv1.10 when transiently expressed in HEK293 cells.…”

Section: Introductionmentioning

confidence: 99%

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Properties of Xenopus Kv1.10 channels expressed in HEK293 cells

2004

Self Cite

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Voltage-gated K+ channels play important roles in shaping the characteristics of action potentials and electrical activity. In a previous study, we isolated cDNAs encoding several distinct K+ channel isoforms, including a novel isoform (XKv1.10) expressed in Xenopus laevis spinal cord neurons and myocytes. Here, we report the biophysical characterization of XKv1.10 expressed in transiently transfected HEK293 cells. Whole cell patch clamp recordings revealed a voltage-gated, rapidly activating and inactivating K+ current. Interestingly, the rate of inactivation of XKv1.10 channels showed apparent voltage dependence, with time constants between 77.7-213.3 ms. The predicted protein sequence of XKv1.10 does not appear to encode an N-terminal inactivating "ball and chain" domain, and instead these channels may inactivate via a C/P-type mechanism. Consistent with this, either increasing the external concentration of K+ or external application of tetraethylammonium caused a decrease in the rate of inactivation. Pharmacologically, XKv1.10 K+ channels were sensitive to 4-aminopyridine and tetraethylammonium with apparent IC50 values of 68.5 microM and 17.1 mM, respectively. When simulated action potentials were used as a voltage command, XKv1.10 was similar to XKv1.4 in that it carried more repolarizing current during the action potential than XKv1.2. However, while XKv1.4 was active during the interspike interval, XKv1.10 and XKv1.2 were not. Overall, the data suggest that XKv1.10 channels make a unique contribution to the developmental maturation of electrical signaling in Xenopus laevis.

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Expression of voltage‐dependent potassium channels in the developing visual system of Xenopus laevis

Pollock

Ferguson

McFarlane

2002

J of Comparative Neurology

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Accumulating evidence suggests that voltage-dependent potassium (Kv) channels have important and varied roles in the development of neuronal and non-neuronal cell types. They have been implicated in processes such as proliferation, cell adhesion, migration, neurite outgrowth, and axon guidance. In this study, we used antibodies against several electrically active Kv channel alpha-subunits (Kv1-4) to describe the spatial and temporal expression patterns of Kv channel subunits in Xenopus laevis retinal ganglion cell (RGC) somata, axons, and growth cones. We found that RGCs express Kv1.3-, Kv1.5-, Kv3.4-, and Kv4.2-like subunits. Each subunit displayed unique cellular and subcellular distributions. Moreover, the expression patterns changed considerably over the major period of Xenopus retinal cell genesis and differentiation. Weak or no immunoreactivity was observed with antibodies against Kv1.1, Kv1.2, Kv1.4, Kv1.6, and Kv3.2 subunits in RGCs or other retinal cell types. In support of our previous pharmacologic evidence implicating Kv channels in RGC axon outgrowth, we found that Kv1.5-, Kv3.4-, and Kv4.2-like proteins, but not Kv1.3-like subunits, are abundantly expressed in RGC growth cones.

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Cloning and expression of three K+ channel cDNAs from Xenopus muscle

Cited by 6 publications

References 52 publications

Dorsal–Ventral Gradient for Neuronal Plasticity in the Embryonic Spinal Cord

Dorsal–Ventral Gradient for Neuronal Plasticity in the Embryonic Spinal Cord

Properties of Xenopus Kv1.10 channels expressed in HEK293 cells

Expression of voltage‐dependent potassium channels in the developing visual system of Xenopus laevis

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