Cloning and Expression of the Human Kv4.3 Potassium Channel

Cloning and expression of the human Kv4.3 potassium channel. We report on the cloning and expression of hKv4.3, a fast inactivating, transient, A-type potassium channel found in both heart and brain that is 91% homologous to the rat Kv4.3 channel. Two isoforms of hKv4.3 were cloned. One is full length (hKv4.3 long), and the other has a 19 amino acid deletion (hKv4.3 short). RT-PCR shows that the brain contains both forms of the channel RNA, whereas the heart predominantly has the longer version. Both versions of the channel were expressed in Xenopus oocytes, and both contain a significant window or noninactivating current seen near potentials of −30 to −40 mV. The inactivation curve for hKv4.3 short is shifted 10 mV positive relative to hKv4.3 long. This causes the peak window current for the short version to occur near −30 mV and the peak for the longer version to be at −40 mV. There was little difference in the recovery from inactivation or in the kinetics of inactivation between the two isoforms of the channel.

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A novel SCN5A mutation associated with long QT-3: altered inactivation kinetics and channel dysfunction

Physiological Genomics ◽

10.1152/physiolgenomics.00039.2002 ◽

2002 ◽

Vol 10 (3) ◽

pp. 191-197 ◽

Cited By ~ 45

Author(s):

Ilaria Rivolta ◽

Colleen E. Clancy ◽

Michihiro Tateyama ◽

Huajun Liu ◽

Silvia G. Priori ◽

...

Keyword(s):

Inactivation Kinetics ◽

Long Qt ◽

Α Subunit ◽

Inactivation Curve ◽

Recovery From Inactivation ◽

Steady State Inactivation ◽

Window Current ◽

Rate Of Recovery ◽

Sustained Inward Current ◽

Congenital Long Qt Syndrome

Mutations in the gene ( SCN5A) encoding the α-subunit of the cardiac Na+ channel cause congenital long QT syndrome (LQT-3). Here we describe a novel LQT-3 mutation I1768V (I1768V) located in the sixth transmembrane spanning segment of domain IV. This mutation is unusual in that it is located within a transmembrane spanning domain and does not promote the typically observed sustained inward current corresponding to a gain of channel function (bursting). Rather, I1768V increases the rate of recovery from inactivation and increases the channel availability, observed as a positive shift of the steady-state inactivation curve (+7.6 mV). Using a Markovian model of the cardiac Na+ channel, we simulated these changes in gating behavior and demonstrated that a small increase in the rate of recovery from inactivation is sufficient to explain all of the experimentally observed current changes. The effect of these alterations in channel gating results in an increase in window current that may act to disrupt cardiac repolarization.

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Effect of pH and inhibitors on beta-amyloid fibril assembly

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100166221 ◽

1996 ◽

Vol 54 ◽

pp. 752-753

Author(s):

Beverly E. Maleeff ◽

Timothy K. Hart ◽

Stephen J. Wood ◽

Ronald Wetzel

Keyword(s):

Amyloid Fibril ◽

Peptide Fragment ◽

Hydrophobic Peptides ◽

Amyloid Fibril Formation ◽

Effects Of Ph ◽

Severity Of The Disease ◽

Kinetics Of ◽

The Brain

Alzheimer's disease is characterized post-mortem in part by abnormal extracellular neuritic plaques found in brain tissue. There appears to be a correlation between the severity of Alzheimer's dementia in vivo and the number of plaques found in particular areas of the brain. These plaques are known to be the deposition sites of fibrils of the protein β-amyloid. It is thought that if the assembly of these plaques could be inhibited, the severity of the disease would be decreased. The peptide fragment Aβ, a precursor of the p-amyloid protein, has a 40 amino acid sequence, and has been shown to be toxic to neuronal cells in culture after an aging process of several days. This toxicity corresponds to the kinetics of in vitro amyloid fibril formation. In this study, we report the biochemical and ultrastructural effects of pH and the inhibitory agent hexadecyl-N-methylpiperidinium (HMP) bromide, one of a class of ionic micellar detergents known to be capable of solubilizing hydrophobic peptides, on the in vitro assembly of the peptide fragment Aβ.

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Subarachnoid diverticulum associated with feline infectious peritonitis in a Siberian cat

Journal of Feline Medicine and Surgery Open Reports ◽

10.1177/2055116920941477 ◽

2020 ◽

Vol 6 (2) ◽

pp. 205511692094147

Author(s):

Christopher Hoey ◽

George Nye ◽

Angela Fadda ◽

Janet Bradshaw ◽

Emi N Barker

Keyword(s):

Cervical Spinal Cord ◽

Serum Biochemistry ◽

Acute Onset ◽

Neurological Deficits ◽

Rt Pcr ◽

Feline Infectious Peritonitis ◽

Case Summary ◽

Choroid Plexitis ◽

The Brain ◽

Feline Coronavirus

Case summary A 7-month-old Siberian cat was presented for investigation of acute onset multifocal neurological deficits. Neurological examination documented dull mental status and an ambulatory left hemiparesis. Serum biochemistry documented marked hyperglobulinaemia. MRI of the brain identified marked leptomeningeal contrast enhancement extending along the brainstem caudally to involve the cranial cervical spinal cord. MRI of the cervical spine further identified a subarachnoid diverticulum that extended from the level of the obex to the C2–C3 vertebrae. Cerebrospinal fluid quantitative RT-PCR was positive for the presence of feline coronavirus. Histopathology revealed pyogranulomatous meningitis and choroid plexitis, uveitis and nephritis. Relevance and novel information This article describes the first reported case of a subarachnoid diverticulum associated with feline infectious peritonitis.

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Modeling temperature- and Cav3 subtype-dependent alterations in T-type calcium channel mediated burst firing

Molecular Brain ◽

10.1186/s13041-021-00813-7 ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Fernando R. Fernandez ◽

Mircea C. Iftinca ◽

Gerald W. Zamponi ◽

Ray W. Turner

Keyword(s):

Calcium Channel ◽

Neuronal Excitability ◽

Neuronal Firing ◽

Mammalian Brain ◽

Peripheral Tissues ◽

Window Current ◽

Modeling Data ◽

The Brain ◽

Firing Neuron ◽

Cav3 Channel

AbstractT-type calcium channels are important regulators of neuronal excitability. The mammalian brain expresses three T-type channel isoforms (Cav3.1, Cav3.2 and Cav3.3) with distinct biophysical properties that are critically regulated by temperature. Here, we test the effects of how temperature affects spike output in a reduced firing neuron model expressing specific Cav3 channel isoforms. The modeling data revealed only a minimal effect on baseline spontaneous firing near rest, but a dramatic increase in rebound burst discharge frequency for Cav3.1 compared to Cav3.2 or Cav3.3 due to differences in window current or activation/recovery time constants. The reduced response by Cav3.2 could optimize its activity where it is expressed in peripheral tissues more subject to temperature variations than Cav3.1 or Cav3.3 channels expressed prominently in the brain. These tests thus reveal that aspects of neuronal firing behavior are critically dependent on both temperature and T-type calcium channel subtype.

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Intranasal insulin improves the structure–function of the brain mitochondrial ATP–sensitive Ca2+ activated potassium channel and respiratory chain activities under diabetic conditions

Biochimica et Biophysica Acta (BBA) - Molecular Basis of Disease ◽

10.1016/j.bbadis.2021.166075 ◽

2021 ◽

Vol 1867 (4) ◽

pp. 166075

Author(s):

Nihad Torabi ◽

Elham Noursadeghi ◽

Farzad Shayanfar ◽

Maryam Nazari ◽

Javad Fahanik-babaei ◽

...

Keyword(s):

Potassium Channel ◽

Structure Function ◽

Respiratory Chain ◽

Intranasal Insulin ◽

The Brain

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Cloning and Expression Analysis of Two Kdm Lysine Demethylases in the Testes of Mature Yaks and Their Sterile Hybrids

Animals ◽

10.3390/ani10030521 ◽

2020 ◽

Vol 10 (3) ◽

pp. 521

Author(s):

Zhenhua Shen ◽

Lin Huang ◽

Suyu Jin ◽

Yucai Zheng

Keyword(s):

Amino Acids ◽

Protein Expression ◽

Male Sterility ◽

Histone Methylation ◽

Real Time Pcr ◽

Cloning And Expression ◽

Rt Pcr ◽

Coding Sequences ◽

Mrna And Protein Expression ◽

Sterile Hybrids

The objective of this study was to explore the molecular mechanism for male sterility of yak hybrids based on two demethylases. Total RNA was extracted from the testes of adult yaks (n = 10) and yak hybrids (cattle–yaks, n = 10). The coding sequences (CDS) of two lysine demethylases (KDMs), KDM1A and KDM4B, were cloned by RT-PCR. The levels of KDM1A and KDM4B in yaks and cattle–yaks testes were detected using Real-time PCR and Western blotting for mRNA and protein, respectively. In addition, the histone methylation modifications of H3K36me3 and H3K27me3 were compared between testes of yaks and cattle–yaks using ELISA. The CDS of KDM1A and KDM4B were obtained from yak testes. The results showed that the CDS of KDM1A exhibited two variants: variant 1 has a CDS of 2622 bp, encoding 873 amino acids, while variant 2 has a CDS of 2562 bp, encoding 853 amino acids. The CDS of the KDM4B gene was 3351 bp in length, encoding 1116 amino acids. The mRNA and protein expression of KDM1A and KDM4B, as well as the level of H3K36me3, were dramatically decreased in the testes of cattle–yaks compared with yaks. The present results suggest that the male sterility of cattle–yaks might be associated with reduced histone methylation modifications.

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Molecular Cloning and Expression of a Kv1.1-like Potassium Channel from the Electric Organ of Electrophorus electricus

The Journal of Membrane Biology ◽

10.1007/s00232-003-0619-x ◽

2003 ◽

Vol 196 (1) ◽

pp. 1-8 ◽

Cited By ~ 10

Author(s):

W. B. Thornhill ◽

I. Watanabe ◽

J. J. Sutachan ◽

M. B. Wu ◽

X. Wu ◽

...

Keyword(s):

Potassium Channel ◽

Molecular Cloning ◽

Electric Organ ◽

Cloning And Expression ◽

Electrophorus Electricus

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Overexpression of the forebrain-specific homeobox gene six3 induces rostral forebrain enlargement in zebrafish

Development ◽

10.1242/dev.125.15.2973 ◽

1998 ◽

Vol 125 (15) ◽

pp. 2973-2982 ◽

Cited By ~ 9

Author(s):

M. Kobayashi ◽

R. Toyama ◽

H. Takeda ◽

I.B. Dawid ◽

K. Kawakami

Keyword(s):

Homeobox Gene ◽

Cloning And Expression ◽

Optic Stalk ◽

Sine Oculis ◽

Murine Homolog ◽

Enhanced Expression ◽

Rostral Region ◽

The Brain ◽

Early Gastrula ◽

Anterior Neural Plate

The Drosophila homeobox gene sine oculis is expressed in the rostral region of the embryo in early development and is essential for eye and brain formation. Its murine homolog, Six3, is expressed in the anterior neural plate and eye anlage, and may have crucial functions in eye and brain development. In this study, we describe the cloning and expression of zebrafish six3, the apparent ortholog of the mouse Six3 gene. Zebrafish six3 transcripts are first seen in hypoblast cells in early gastrula embryos and are found in the anterior axial mesendoderm through gastrulation. six3 expression in the head ectoderm begins at late gastrula. Throughout the segmentation period, six3 is expressed in the rostral region of the prospective forebrain. Overexpression of six3 in zebrafish embryos induced enlargement of the rostral forebrain, enhanced expression of pax2 in the optic stalk and led to a general disorganization of the brain. Disruption of either the Six domain or the homeodomain abolish these effects, implying that these domains are essential for six3 gene function. Our results suggest that the vertebrate Six3 genes are involved in the formation of the rostral forebrain.

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