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Giffen KP, Liu H, Yamane KL, Li Y, Chen L, Kramer KL, Zallocchi M, He DZ. Molecular Specializations Underlying Phenotypic Differences in Inner Ear Hair Cells of Zebrafish and Mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.24.595729. [PMID: 38826418 PMCID: PMC11142236 DOI: 10.1101/2024.05.24.595729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
Hair cells (HCs) are the sensory receptors of the auditory and vestibular systems in the inner ears of vertebrates that selectively transduce mechanical stimuli into electrical activity. Although all HCs have the hallmark stereocilia bundle for mechanotransduction, HCs in non-mammals and mammals differ in their molecular specialization in the apical, basolateral and synaptic membranes. HCs of non-mammals, such as zebrafish (zHCs), are electrically tuned to specific frequencies and possess an active process in the stereocilia bundle to amplify sound signals. Mammalian cochlear HCs, in contrast, are not electrically tuned and achieve amplification by somatic motility of outer HCs (OHCs). To understand the genetic mechanisms underlying differences among adult zebrafish and mammalian cochlear HCs, we compared their RNA-seq-characterized transcriptomes, focusing on protein-coding orthologous genes related to HC specialization. There was considerable shared expression of gene orthologs among the HCs, including those genes associated with mechanotransduction, ion transport/channels, and synaptic signaling. For example, both zebrafish and mouse HCs express Tmc1, Lhfpl5, Tmie, Cib2, Cacna1d, Cacnb2, Otof, Pclo and Slc17a8. However, there were some notable differences in expression among zHCs, OHCs, and inner HCs (IHCs), which likely underlie the distinctive physiological properties of each cell type. Tmc2 and Cib3 were not detected in adult mouse HCs but tmc2a and b and cib3 were highly expressed in zHCs. Mouse HCs express Kcna10, Kcnj13, Kcnj16, and Kcnq4, which were not detected in zHCs. Chrna9 and Chrna10 were expressed in mouse HCs. In contrast, chrna10 was not detected in zHCs. OHCs highly express Slc26a5 which encodes the motor protein prestin that contributes to OHC electromotility. However, zHCs have only weak expression of slc26a5, and subsequently showed no voltage dependent electromotility when measured. Notably, the zHCs expressed more paralogous genes including those associated with HC-specific functions and transcriptional activity, though it is unknown whether they have functions similar to their mammalian counterparts. There was overlap in the expressed genes associated with a known hearing phenotype. Our analyses unveil substantial differences in gene expression patterns that may explain phenotypic specialization of zebrafish and mouse HCs. This dataset also includes several protein-coding genes to further the functional characterization of HCs and study of HC evolution from non-mammals to mammals.
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Affiliation(s)
- Kimberlee P. Giffen
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia at Augusta University, Augusta, GA, USA
- Augusta University/University of Georgia Medical Partnership, Athens, GA, USA
| | - Huizhan Liu
- Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, NE, USA
| | - Kacey L. Yamane
- Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, NE, USA
| | - Yi Li
- Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, NE, USA
- Department of Otorhinolaryngology, Beijing Tongren Hospital, Beijing Capital Medical University, Beijing, China
| | - Lei Chen
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN, USA
| | - Ken L. Kramer
- Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, NE, USA
| | - Marisa Zallocchi
- Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, NE, USA
| | - David Z.Z. He
- Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, NE, USA
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Plazas PV, Elgoyhen AB. The Cholinergic Lateral Line Efferent Synapse: Structural, Functional and Molecular Similarities With Those of the Cochlea. Front Cell Neurosci 2021; 15:765083. [PMID: 34712122 PMCID: PMC8545859 DOI: 10.3389/fncel.2021.765083] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 09/21/2021] [Indexed: 11/25/2022] Open
Abstract
Vertebrate hair cell (HC) systems are innervated by efferent fibers that modulate their response to external stimuli. In mammals, the best studied efferent-HC synapse, the cholinergic medial olivocochlear (MOC) efferent system, makes direct synaptic contacts with HCs. The net effect of MOC activity is to hyperpolarize HCs through the activation of α9α10 nicotinic cholinergic receptors (nAChRs) and the subsequent activation of Ca2+-dependent SK2 potassium channels. A serious obstacle in research on many mammalian sensory systems in their native context is that their constituent neurons are difficult to access even in newborn animals, hampering circuit observation, mapping, or controlled manipulation. By contrast, fishes and amphibians have a superficial and accessible mechanosensory system, the lateral line (LL), which circumvents many of these problems. LL responsiveness is modulated by efferent neurons which aid to distinguish between external and self-generated stimuli. One component of the LL efferent system is cholinergic and its activation inhibits LL afferent activity, similar to what has been described for MOC efferents. The zebrafish (Danio rerio) has emerged as a powerful model system for studying human hearing and balance disorders, since LL HC are structurally and functionally analogous to cochlear HCs, but are optically and pharmacologically accessible within an intact specimen. Complementing mammalian studies, zebrafish have been used to gain significant insights into many facets of HC biology, including mechanotransduction and synaptic physiology as well as mechanisms of both hereditary and acquired HC dysfunction. With the rise of the zebrafish LL as a model in which to study auditory system function and disease, there has been an increased interest in studying its efferent system and evaluate the similarity between mammalian and piscine efferent synapses. Advances derived from studies in zebrafish include understanding the effect of the LL efferent system on HC and afferent activity, and revealing that an α9-containing nAChR, functionally coupled to SK channels, operates at the LL efferent synapse. In this review, we discuss the tools and findings of these recent investigations into zebrafish efferent-HC synapse, their commonalities with the mammalian counterpart and discuss several emerging areas for future studies.
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Affiliation(s)
- Paola V Plazas
- Instituto de Farmacología, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Ana Belén Elgoyhen
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
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Numata T, Sato-Numata K, Yoshino M. BK Channels Are Activated by Functional Coupling With L-Type Ca 2+ Channels in Cricket Myocytes. FRONTIERS IN INSECT SCIENCE 2021; 1:662414. [PMID: 38468898 PMCID: PMC10926482 DOI: 10.3389/finsc.2021.662414] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 03/15/2021] [Indexed: 03/13/2024]
Abstract
Large-conductance calcium (Ca2+)-activated potassium (K+) (BK) channel activation is important for feedback control of Ca2+ influx and cell excitability during spontaneous muscle contraction. To characterize endogenously expressed BK channels and evaluate the functional relevance of Ca2+ sources leading to BK activity, patch-clamp electrophysiology was performed on cricket oviduct myocytes to obtain single-channel recordings. The single-channel conductance of BK channels was 120 pS, with increased activity resulting from membrane depolarization or increased intracellular Ca2+ concentration. Extracellular application of tetraethylammonium (TEA) and iberiotoxin (IbTX) suppressed single-channel current amplitude. These results indicate that BK channels are endogenously expressed in cricket oviduct myocytes. Ca2+ release from internal Ca2+ stores and Ca2+ influx via the plasma membrane, which affect BK activity, were investigated. Extracellular Ca2+ removal nullified BK activity. Administration of ryanodine and caffeine reduced BK activity. Administration of L-type Ca2+ channel activity regulators (Bay K 8644 and nifedipine) increased and decreased BK activity, respectively. Finally, the proximity between the L-type Ca2+ channel and BK was investigated. Administration of Bay K 8644 to the microscopic area within the pipette increased BK activity. However, this increase was not observed at a sustained depolarizing potential. These results show that BK channels are endogenously expressed in cricket oviduct myocytes and that BK activity is regulated by L-type Ca2+ channel activity and Ca2+ release from Ca2+ stores. Together, these results show that functional coupling between L-type Ca2+ and BK channels may underlie the molecular basis of spontaneous rhythmic contraction.
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Affiliation(s)
- Tomohiro Numata
- Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan
- Department of Biology, Tokyo Gakugei University, Tokyo, Japan
| | - Kaori Sato-Numata
- Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan
- Department of Biology, Tokyo Gakugei University, Tokyo, Japan
- Japan Society for the Promotion of Science, Tokyo, Japan
| | - Masami Yoshino
- Department of Biology, Tokyo Gakugei University, Tokyo, Japan
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Silic MR, Black MM, Zhang G. Phylogenetic and developmental analyses indicate complex functions of calcium-activated potassium channels in zebrafish embryonic development. Dev Dyn 2021; 250:1477-1493. [PMID: 33728688 PMCID: PMC8518378 DOI: 10.1002/dvdy.329] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Revised: 03/09/2021] [Accepted: 03/13/2021] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Calcium-activated potassium channels (KCa) are a specific type of potassium channel activated by intracellular calcium concentration changes. This group of potassium channels plays fundamental roles ranging from regulating neuronal excitability to immune cell activation. Many human diseases such as schizophrenia, hypertension, epilepsy, and cancers have been linked to mutations in this group of potassium channels. Although the KCa channels have been extensively studied electrophysiologically and pharmacologically, their spatiotemporal gene expression during embryogenesis remains mostly unknown. RESULTS Using zebrafish as a model, we identified and renamed 14 KCa genes. We further performed phylogenetic and syntenic analyses on vertebrate KCa genes. Our data revealed that the number of KCa genes in zebrafish was increased, most likely due to teleost-specific whole-genome duplication. Moreover, we examined zebrafish KCa gene expression during early embryogenesis. The duplicated ohnologous genes show distinct and overlapped gene expression. Furthermore, we found that zebrafish KCa genes are expressed in various tissues and organs (somites, fins, olfactory regions, eye, kidney, and so on) and neuronal tissues, suggesting that they may play important roles during zebrafish embryogenesis. CONCLUSIONS Our phylogenetic and developmental analyses shed light on the potential functions of the KCa genes during embryogenesis related to congenital diseases and human channelopathies.
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Affiliation(s)
- Martin R Silic
- Department of Comparative Pathobiology, Purdue University, West Lafayette, Indiana, USA
| | - Maya M Black
- Department of Comparative Pathobiology, Purdue University, West Lafayette, Indiana, USA
| | - GuangJun Zhang
- Department of Comparative Pathobiology, Purdue University, West Lafayette, Indiana, USA.,Purdue University Center for Cancer Research, West Lafayette, Indiana, USA.,Purdue Institute for Inflammation, Immunology and Infectious Diseases (PI4D), West Lafayette, Indiana, USA.,Purdue Institute for Integrative Neuroscience; Purdue University, West Lafayette, Indiana, USA
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Pineda S, Nikolova-Krstevski V, Leimena C, Atkinson AJ, Altekoester AK, Cox CD, Jacoby A, Huttner IG, Ju YK, Soka M, Ohanian M, Trivedi G, Kalvakuri S, Birker K, Johnson R, Molenaar P, Kuchar D, Allen DG, van Helden DF, Harvey RP, Hill AP, Bodmer R, Vogler G, Dobrzynski H, Ocorr K, Fatkin D. Conserved Role of the Large Conductance Calcium-Activated Potassium Channel, K Ca1.1, in Sinus Node Function and Arrhythmia Risk. CIRCULATION-GENOMIC AND PRECISION MEDICINE 2021; 14:e003144. [PMID: 33629867 DOI: 10.1161/circgen.120.003144] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND KCNMA1 encodes the α-subunit of the large-conductance Ca2+-activated K+ channel, KCa1.1, and lies within a linkage interval for atrial fibrillation (AF). Insights into the cardiac functions of KCa1.1 are limited, and KCNMA1 has not been investigated as an AF candidate gene. METHODS The KCNMA1 gene was sequenced in 118 patients with familial AF. The role of KCa1.1 in normal cardiac structure and function was evaluated in humans, mice, zebrafish, and fly. A novel KCNMA1 variant was functionally characterized. RESULTS A complex KCNMA1 variant was identified in 1 kindred with AF. To evaluate potential disease mechanisms, we first evaluated the distribution of KCa1.1 in normal hearts using immunostaining and immunogold electron microscopy. KCa1.1 was seen throughout the atria and ventricles in humans and mice, with strong expression in the sinus node. In an ex vivo murine sinoatrial node preparation, addition of the KCa1.1 antagonist, paxilline, blunted the increase in beating rate induced by adrenergic receptor stimulation. Knockdown of the KCa1.1 ortholog, kcnma1b, in zebrafish embryos resulted in sinus bradycardia with dilatation and reduced contraction of the atrium and ventricle. Genetic inactivation of the Drosophila KCa1.1 ortholog, slo, systemically or in adult stages, also slowed the heartbeat and produced fibrillatory cardiac contractions. Electrophysiological characterization of slo-deficient flies revealed bursts of action potentials, reflecting increased events of fibrillatory arrhythmias. Flies with cardiac-specific overexpression of the human KCNMA1 mutant also showed increased heart period and bursts of action potentials, similar to the KCa1.1 loss-of-function models. CONCLUSIONS Our data point to a highly conserved role of KCa1.1 in sinus node function in humans, mice, zebrafish, and fly and suggest that KCa1.1 loss of function may predispose to AF.
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Affiliation(s)
- Santiago Pineda
- Development, Aging & Regeneration Program, Sanford-Burnham Prebys Medical Discovery Institute, La Jolla, CA (S.P., S.K., K.B., R.B., G.V., K.O.)
| | - Vesna Nikolova-Krstevski
- Victor Chang Cardiac Research Institute, Darlinghurst (V.N.-K., C.L., A.-K.A., C.D.C., A.J., I.G.H., M.S., M.O., G.T., R.J., R.P.H., A.P.H., D.F.).,Faculty of Medicine, UNSW Sydney, Kensington (V.N.-K., I.G.H., R.J., R.P.H., A.P.H., D.F.)
| | - Christiana Leimena
- Victor Chang Cardiac Research Institute, Darlinghurst (V.N.-K., C.L., A.-K.A., C.D.C., A.J., I.G.H., M.S., M.O., G.T., R.J., R.P.H., A.P.H., D.F.)
| | - Andrew J Atkinson
- Institute of Cardiovascular Sciences, University of Manchester, United Kingdom (A.J.A., H.D.)
| | - Ann-Kristin Altekoester
- Victor Chang Cardiac Research Institute, Darlinghurst (V.N.-K., C.L., A.-K.A., C.D.C., A.J., I.G.H., M.S., M.O., G.T., R.J., R.P.H., A.P.H., D.F.)
| | - Charles D Cox
- Victor Chang Cardiac Research Institute, Darlinghurst (V.N.-K., C.L., A.-K.A., C.D.C., A.J., I.G.H., M.S., M.O., G.T., R.J., R.P.H., A.P.H., D.F.)
| | - Arie Jacoby
- Victor Chang Cardiac Research Institute, Darlinghurst (V.N.-K., C.L., A.-K.A., C.D.C., A.J., I.G.H., M.S., M.O., G.T., R.J., R.P.H., A.P.H., D.F.)
| | - Inken G Huttner
- Victor Chang Cardiac Research Institute, Darlinghurst (V.N.-K., C.L., A.-K.A., C.D.C., A.J., I.G.H., M.S., M.O., G.T., R.J., R.P.H., A.P.H., D.F.).,Faculty of Medicine, UNSW Sydney, Kensington (V.N.-K., I.G.H., R.J., R.P.H., A.P.H., D.F.)
| | - Yue-Kun Ju
- Bosch Institute, University of Sydney, Camperdown (Y.-K.J., D.G.A.)
| | - Magdalena Soka
- Victor Chang Cardiac Research Institute, Darlinghurst (V.N.-K., C.L., A.-K.A., C.D.C., A.J., I.G.H., M.S., M.O., G.T., R.J., R.P.H., A.P.H., D.F.)
| | - Monique Ohanian
- Victor Chang Cardiac Research Institute, Darlinghurst (V.N.-K., C.L., A.-K.A., C.D.C., A.J., I.G.H., M.S., M.O., G.T., R.J., R.P.H., A.P.H., D.F.)
| | - Gunjan Trivedi
- Victor Chang Cardiac Research Institute, Darlinghurst (V.N.-K., C.L., A.-K.A., C.D.C., A.J., I.G.H., M.S., M.O., G.T., R.J., R.P.H., A.P.H., D.F.)
| | - Sreehari Kalvakuri
- Development, Aging & Regeneration Program, Sanford-Burnham Prebys Medical Discovery Institute, La Jolla, CA (S.P., S.K., K.B., R.B., G.V., K.O.)
| | - Katja Birker
- Development, Aging & Regeneration Program, Sanford-Burnham Prebys Medical Discovery Institute, La Jolla, CA (S.P., S.K., K.B., R.B., G.V., K.O.)
| | - Renee Johnson
- Victor Chang Cardiac Research Institute, Darlinghurst (V.N.-K., C.L., A.-K.A., C.D.C., A.J., I.G.H., M.S., M.O., G.T., R.J., R.P.H., A.P.H., D.F.).,Faculty of Medicine, UNSW Sydney, Kensington (V.N.-K., I.G.H., R.J., R.P.H., A.P.H., D.F.)
| | - Peter Molenaar
- Faculty of Health, Queensland University of Technology (P.M.).,School of Medicine, University of Queensland, Prince Charles Hospital, Brisbane, Queensland, Australia (P.M.)
| | - Dennis Kuchar
- Cardiology Department, St Vincent's Hospital, Darlinghurst (D.K., D.F.)
| | - David G Allen
- Bosch Institute, University of Sydney, Camperdown (Y.-K.J., D.G.A.)
| | - Dirk F van Helden
- University of Newcastle and Hunter Medical Research Institute, NSW, Australia (D.F.v.H.)
| | - Richard P Harvey
- Victor Chang Cardiac Research Institute, Darlinghurst (V.N.-K., C.L., A.-K.A., C.D.C., A.J., I.G.H., M.S., M.O., G.T., R.J., R.P.H., A.P.H., D.F.).,Faculty of Medicine, UNSW Sydney, Kensington (V.N.-K., I.G.H., R.J., R.P.H., A.P.H., D.F.)
| | - Adam P Hill
- Victor Chang Cardiac Research Institute, Darlinghurst (V.N.-K., C.L., A.-K.A., C.D.C., A.J., I.G.H., M.S., M.O., G.T., R.J., R.P.H., A.P.H., D.F.).,Faculty of Medicine, UNSW Sydney, Kensington (V.N.-K., I.G.H., R.J., R.P.H., A.P.H., D.F.)
| | - Rolf Bodmer
- Development, Aging & Regeneration Program, Sanford-Burnham Prebys Medical Discovery Institute, La Jolla, CA (S.P., S.K., K.B., R.B., G.V., K.O.)
| | - Georg Vogler
- Development, Aging & Regeneration Program, Sanford-Burnham Prebys Medical Discovery Institute, La Jolla, CA (S.P., S.K., K.B., R.B., G.V., K.O.)
| | - Halina Dobrzynski
- Institute of Cardiovascular Sciences, University of Manchester, United Kingdom (A.J.A., H.D.).,Jagiellonian University Medical College, Cracow, Poland (H.D.)
| | - Karen Ocorr
- Development, Aging & Regeneration Program, Sanford-Burnham Prebys Medical Discovery Institute, La Jolla, CA (S.P., S.K., K.B., R.B., G.V., K.O.)
| | - Diane Fatkin
- Victor Chang Cardiac Research Institute, Darlinghurst (V.N.-K., C.L., A.-K.A., C.D.C., A.J., I.G.H., M.S., M.O., G.T., R.J., R.P.H., A.P.H., D.F.).,Faculty of Medicine, UNSW Sydney, Kensington (V.N.-K., I.G.H., R.J., R.P.H., A.P.H., D.F.).,Cardiology Department, St Vincent's Hospital, Darlinghurst (D.K., D.F.)
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Clusin WT, Wu TH, Shi LF, Kao PN. Further studies of ion channels in the electroreceptor of the skate through deep sequencing, cloning and cross species comparisons. Gene 2019; 718:143989. [PMID: 31326551 DOI: 10.1016/j.gene.2019.143989] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Revised: 06/23/2019] [Accepted: 07/17/2019] [Indexed: 11/25/2022]
Abstract
Our comparative studies seek to understand the structure and function of ion channels in cartilaginous fish that can detect very low voltage gradients in seawater. The principal channels of the electroreceptor include a calcium activated K channel whose α subunit is Kcnma1, and a voltage-dependent calcium channel, Cacna1d. It has also been suggested based on physiological and pharmacological evidence that a voltage-gated K channel is present in the basal membranes of the receptor cells which modulates synaptic transmitter release. Large conductance calcium-activated K channels (BK) are comprised of four α subunits, encoded by Kcnma1 and modulatory β subunits of the Kcnmb class. We recently cloned and published the skate Kcnma1 gene and most of Kcnmb4 using purified mRNA of homogenized electroreceptors. Bellono et al. have recently performed RNA sequencing (RNA-seq) on purified mRNA from skate electroreceptors and found several ion channels including Kcnma1. We searched the Bellono et al. RNA-seq repository for additional channels and subunits. Our most significant findings are the presence of two Shaker type voltage dependent K channel sequences which are grouped together as isoforms in the data repository. The larger of these is a skate ortholog of the voltage dependent fast potassium channel Kv1.1, which is expressed at appreciable levels. The second ortholog is similar to Kv1.5 but has fewer N-terminal amino acids than other species. The sequence for Kv1.5 in the skate is very strongly aligned with the recently reported sequence for potassium channels in the electroreceptors of the cat shark, S. retifer, which also modulate synaptic transmission. The latter channel was designated as Kv1.3 in the initial report, but we suggest that these channels are actually orthologs of each other, and that Kv1.5 is the prevailing designation. We also found a beta subunit sequence (Kcnab2) which may co-assemble with one or both of the voltage gated channels. The new channels and subunits were verified by RT-PCR and the Kv1.1 sequence was confirmed by cloning. We also searched the RNA-seq repository for accessory subunits of Kcnma1, and found a computer-generated assembly that contained a complete sequence of its β subunit, Kcnmb2. Skate Kcnmb2 has a total of 279 amino acids, with 51 novel amino acids at the N-terminus which may play a specific physiological role. This sequence was confirmed by PCR and cloning. However, skate Kcnmb2 is expressed at low levels in the electroreceptor compared to Kcnma1 and skate Kcnmb1 is absent. The evolutionary origin of the newly described K channels and their subunits was studied by alignments with mammalian sequences, including human, and also those in related fish: the whale shark (R. typus), the ghost shark (C.milii), and (S. retifer). There are also orthologous K channels of the lamprey, which has electroreceptors. Tree building and bootstrap programs were used to confirm phylogenetic inferences. Further research should focus on the subcellular locations of these channels, their gating behavior, and the effects of accessory subunits on gating.
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Affiliation(s)
- William T Clusin
- Department of Medicine, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, CA 94305, United States of America.
| | - Ting-Hsuan Wu
- Department of Medicine, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, CA 94305, United States of America
| | - Ling-Fang Shi
- Department of Medicine, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, CA 94305, United States of America
| | - Peter N Kao
- Department of Medicine, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, CA 94305, United States of America
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Ramallo MR, Morandini L, Birba A, Somoza GM, Pandolfi M. From molecule to behavior: Brain aromatase (cyp19a1b) characterization, expression analysis and its relation with social status and male agonistic behavior in a Neotropical cichlid fish. Horm Behav 2017; 89:176-188. [PMID: 28167134 DOI: 10.1016/j.yhbeh.2017.02.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Revised: 02/01/2017] [Accepted: 02/01/2017] [Indexed: 11/28/2022]
Abstract
The enzyme aromatase, responsible for the conversion of C19 androgens to C18 estrogens, exists as two paralogue copies in teleost fish: Cyp19a1a mostly expressed in the gonads, referred as gonadal aromatase, and Cyp19a1b, mostly expressed in the brain, accordingly known as brain aromatase. The neural localization of Cyp19a1b is greatly contained within the social behavior network and mesolimbic reward system in fish, suggesting a strong role of estrogen synthesis in the regulation of social behavior. In this work we aimed to analyze the variation in cyp19a1b expression in brain and pituitary of males of a highly social cichlid, Cichlasoma dimerus (locally known as chanchita), and its relation with inter-individual variability in agonistic behavior in a communal social environment. We first characterized chanchita's cyp19a1b mRNA and deduced amino acid sequence, which showed a high degree of conservation when compared to other teleost brain aromatase sequences, and its tissue expression patterns. Within the brain, Cyp19a1b was solely detected at putative radial glial cells of the forebrain, close to the brain ventricles. We then studied the relative expression levels of cyp19a1b by Real Time PCR in the brain and pituitary of males of different social status, territorial vs. non-territorial, and its relationship with an index of agonistic behavior. We found that even though, brain aromatase expression did not differ between types of males, pituitary cyp19a1b expression levels positively correlated with the index of agonistic behavior. This suggests a novel role of the pituitary in the regulation of social behavior by local estrogen synthesis.
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Affiliation(s)
- Martín R Ramallo
- Laboratorio de Neuroendocrinología y Comportamiento, DBBE, IBBEA-CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, CABA, Argentina
| | - Leonel Morandini
- Laboratorio de Neuroendocrinología y Comportamiento, DBBE, IBBEA-CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, CABA, Argentina
| | - Agustina Birba
- Laboratorio de Ictiofisiología y Acuicultura, IIB-INTECH, CONICET, UNSAM, Chascomús, Buenos Aires, Argentina
| | - Gustavo M Somoza
- Laboratorio de Ictiofisiología y Acuicultura, IIB-INTECH, CONICET, UNSAM, Chascomús, Buenos Aires, Argentina
| | - Matías Pandolfi
- Laboratorio de Neuroendocrinología y Comportamiento, DBBE, IBBEA-CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, CABA, Argentina.
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Vicens A, Andrade‐López K, Cortez D, Gutiérrez RM, Treviño CL. Premammalian origin of the sperm-specific Slo3 channel. FEBS Open Bio 2017; 7:382-390. [PMID: 28286733 PMCID: PMC5337896 DOI: 10.1002/2211-5463.12186] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Revised: 12/01/2016] [Accepted: 12/16/2016] [Indexed: 01/05/2023] Open
Abstract
Slo3 is a sperm-specific potassium (K+) channel essential for male fertility. Slo3 channels have so far been considered to be specific to mammals. Through exploratory genomics, we identified the Slo3 gene in the genome of terrestrial (birds and reptiles) and aquatic (fish) vertebrates. In the case of fish, Slo3 has undergone several episodes of gene loss. Transcriptomic analysis showed that vertebrate Slo3 transcript orthologues are predominantly expressed in testis, in concordance with the mammalian Slo3. We conclude that the Slo3 gene arose during the radiation of early vertebrates, much earlier than previously thought. Our findings add to the growing evidence indicating that the phylogenetic profiles of sperm-specific channels are intermittent throughout metazoan evolution, which probably reflects the adaptation of sperm to different ionic milieus and fertilization environments.
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Affiliation(s)
- Alberto Vicens
- Departamento de Genética del Desarrollo y Fisiología MolecularInstituto de BiotecnologíaUniversidad Nacional Autónoma de MéxicoCuernavaca MorelosMéxico
| | - Karla Andrade‐López
- Departamento de Genética del Desarrollo y Fisiología MolecularInstituto de BiotecnologíaUniversidad Nacional Autónoma de MéxicoCuernavaca MorelosMéxico
| | - Diego Cortez
- Centro de Ciencias GenómicasUniversidad Nacional Autónoma de MéxicoCuernavaca MorelosMéxico
| | - Rosa María Gutiérrez
- Departamento de Microbiología MolecularInstituto de BiotecnologíaUniversidad Nacional Autónoma de MéxicoCuernavaca MorelosMéxico
| | - Claudia L. Treviño
- Departamento de Genética del Desarrollo y Fisiología MolecularInstituto de BiotecnologíaUniversidad Nacional Autónoma de MéxicoCuernavaca MorelosMéxico
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9
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Neuroanatomical Evidence for Catecholamines as Modulators of Audition and Acoustic Behavior in a Vocal Teleost. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 877:439-75. [PMID: 26515325 DOI: 10.1007/978-3-319-21059-9_19] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The plainfin midshipman fish (Porichthys notatus) is a well-studied model to understand the neural and endocrine mechanisms underlying vocal-acoustic communication across vertebrates. It is well established that steroid hormones such as estrogen drive seasonal peripheral auditory plasticity in female Porichthys in order to better encode the male's advertisement call. However, little is known of the neural substrates that underlie the motivation and coordinated behavioral response to auditory social signals. Catecholamines, which include dopamine and noradrenaline, are good candidates for this function, as they are thought to modulate the salience of and reinforce appropriate behavior to socially relevant stimuli. This chapter summarizes our recent studies which aimed to characterize catecholamine innervation in the central and peripheral auditory system of Porichthys as well as test the hypotheses that innervation of the auditory system is seasonally plastic and catecholaminergic neurons are activated in response to conspecific vocalizations. Of particular significance is the discovery of direct dopaminergic innervation of the saccule, the main hearing end organ, by neurons in the diencephalon, which also robustly innervate the cholinergic auditory efferent nucleus in the hindbrain. Seasonal changes in dopamine innervation in both these areas appear dependent on reproductive state in females and may ultimately function to modulate the sensitivity of the peripheral auditory system as an adaptation to the seasonally changing soundscape. Diencephalic dopaminergic neurons are indeed active in response to exposure to midshipman vocalizations and are in a perfect position to integrate the detection and appropriate motor response to conspecific acoustic signals for successful reproduction.
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10
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Forlano PM, Maruska KP, Sisneros JA, Bass AH. Hormone-Dependent Plasticity of Auditory Systems in Fishes. HEARING AND HORMONES 2016. [DOI: 10.1007/978-3-319-26597-1_2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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11
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King BL, Shi LF, Kao P, Clusin WT. Calcium activated K⁺ channels in the electroreceptor of the skate confirmed by cloning. Details of subunits and splicing. Gene 2015; 578:63-73. [PMID: 26687710 DOI: 10.1016/j.gene.2015.12.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 12/07/2015] [Indexed: 12/22/2022]
Abstract
Elasmobranchs detect small potentials using excitable cells of the ampulla of Lorenzini which have calcium-activated K(+) channels, first described in 1974. A distinctive feature of the outward current in voltage clamped ampullae is its apparent insensitivity to voltage. The sequence of a BK channel α isoform expressed in the ampulla of the skate was characterized. A signal peptide is present at the beginning of the gene. When compared to human isoform 1 (the canonical sequence), the largest difference was absence of a 59 amino acid region from the S8-S9 intra-cellular linker that contains the strex regulatory domain. The ampulla isoform was also compared with the isoform predicted in late skate embryos where strex was also absent. The BK voltage sensors were conserved in both skate isoforms. Differences between the skate and human BK channel included alternative splicing. Alternative splicing occurs at seven previously defined sites that are characteristic for BK channels in general and hair cells in particular. Skate BK sequences were highly similar to the Australian ghost shark and several other vertebrate species. Based on alignment of known BK sequences with the skate genome and transcriptome, there are at least two isoforms of Kcnma1α expressed in the skate. One of the β subunits (β4), which is known to decrease voltage sensitivity, was also identified in the skate genome and transcriptome and in the ampulla. These studies advance our knowledge of BK channels and suggest further studies in the ampulla and other excitable tissues.
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Affiliation(s)
- Benjamin L King
- Mount Desert Island Biological Laboratory, Salisbury Cove, ME 04672, United States
| | - Ling Fang Shi
- Department of Medicine, Stanford University Medical School, Stanford, CA 94305, United States
| | - Peter Kao
- Department of Medicine, Stanford University Medical School, Stanford, CA 94305, United States
| | - William T Clusin
- Department of Medicine, Stanford University Medical School, Stanford, CA 94305, United States.
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12
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Faber-Hammond J, Samanta MP, Whitchurch EA, Manning D, Sisneros JA, Coffin AB. Saccular Transcriptome Profiles of the Seasonal Breeding Plainfin Midshipman Fish (Porichthys notatus), a Teleost with Divergent Sexual Phenotypes. PLoS One 2015; 10:e0142814. [PMID: 26560106 PMCID: PMC4641692 DOI: 10.1371/journal.pone.0142814] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Accepted: 10/27/2015] [Indexed: 11/18/2022] Open
Abstract
Acoustic communication is essential for the reproductive success of the plainfin midshipman fish (Porichthys notatus). During the breeding season, type I males use acoustic cues to advertise nest location to potential mates, creating an audible signal that attracts reproductive females. Type II (sneaker) males also likely use this social acoustic signal to find breeding pairs from which to steal fertilizations. Estrogen-induced changes in the auditory system of breeding females are thought to enhance neural encoding of the advertisement call, and recent anatomical data suggest the saccule (the main auditory end organ) as one possible target for this seasonal modulation. Here we describe saccular transcriptomes from all three sexual phenotypes (females, type I and II males) collected during the breeding season as a first step in understanding the mechanisms underlying sexual phenotype-specific and seasonal differences in auditory function. We used RNA-Seq on the Ion Torrent platform to create a combined transcriptome dataset containing over 79,000 assembled transcripts representing almost 9,000 unique annotated genes. These identified genes include several with known inner ear function and multiple steroid hormone receptors. Transcripts most closely matched to published genomes of nile tilapia and large yellow croaker, inconsistent with the phylogenetic relationship between these species but consistent with the importance of acoustic communication in their life-history strategies. We then compared the RNA-Seq results from the saccules of reproductive females with a separate transcriptome from the non-reproductive female phenotype and found over 700 differentially expressed transcripts, including members of the Wnt and Notch signaling pathways that mediate cell proliferation and hair cell addition in the inner ear. These data constitute a valuable resource for furthering our understanding of the molecular basis for peripheral auditory function as well as a range of future midshipman and cross-species comparative studies of the auditory periphery.
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Affiliation(s)
- Joshua Faber-Hammond
- College of Arts and Sciences, Washington State University, Vancouver, WA, United States of America
| | | | - Elizabeth A. Whitchurch
- Department of Biological Sciences, Humboldt State University, Arcata, CA, United States of America
| | - Dustin Manning
- College of Arts and Sciences, Washington State University, Vancouver, WA, United States of America
| | - Joseph A. Sisneros
- Department of Psychology, University of Washington, Seattle, WA, United States of America
| | - Allison B. Coffin
- College of Arts and Sciences, Washington State University, Vancouver, WA, United States of America
- Department of Integrative Physiology and Neuroscience, Washington State University, Vancouver, WA, United States of America
- * E-mail:
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13
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Forlano PM, Sisneros JA, Rohmann KN, Bass AH. Neuroendocrine control of seasonal plasticity in the auditory and vocal systems of fish. Front Neuroendocrinol 2015; 37:129-45. [PMID: 25168757 PMCID: PMC4342331 DOI: 10.1016/j.yfrne.2014.08.002] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Revised: 08/09/2014] [Accepted: 08/14/2014] [Indexed: 11/27/2022]
Abstract
Seasonal changes in reproductive-related vocal behavior are widespread among fishes. This review highlights recent studies of the vocal plainfin midshipman fish, Porichthys notatus, a neuroethological model system used for the past two decades to explore neural and endocrine mechanisms of vocal-acoustic social behaviors shared with tetrapods. Integrative approaches combining behavior, neurophysiology, neuropharmacology, neuroanatomy, and gene expression methodologies have taken advantage of simple, stereotyped and easily quantifiable behaviors controlled by discrete neural networks in this model system to enable discoveries such as the first demonstration of adaptive seasonal plasticity in the auditory periphery of a vertebrate as well as rapid steroid and neuropeptide effects on vocal physiology and behavior. This simple model system has now revealed cellular and molecular mechanisms underlying seasonal and steroid-driven auditory and vocal plasticity in the vertebrate brain.
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Affiliation(s)
- Paul M Forlano
- Department of Biology, Brooklyn College, City University of New York, Brooklyn, NY 11210, United States; Programs in Neuroscience, Ecology, Evolutionary Biology and Behavior, and Behavioral and Cognitive Neuroscience, The Graduate Center, City University of New York, New York, NY 10016, United States; Aquatic Research and Environmental Assessment Center, Brooklyn College, Brooklyn, NY 11210, United States.
| | - Joseph A Sisneros
- Department of Psychology, University of Washington, Seattle, WA 98195, United States; Department of Biology, University of Washington, Seattle, WA 98195, United States; Virginia Merrill Bloedel Hearing Research Center, Seattle, WA 98195, United States
| | - Kevin N Rohmann
- Department of Otolaryngology, Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21205, United States
| | - Andrew H Bass
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853, United States; Bodega Marine Laboratory, University of California, Bodega Bay, CA, 94923, United States
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14
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Kulke D, von Samson-Himmelstjerna G, Miltsch SM, Wolstenholme AJ, Jex AR, Gasser RB, Ballesteros C, Geary TG, Keiser J, Townson S, Harder A, Krücken J. Characterization of the Ca2+-gated and voltage-dependent K+-channel Slo-1 of nematodes and its interaction with emodepside. PLoS Negl Trop Dis 2014; 8:e3401. [PMID: 25521608 PMCID: PMC4270693 DOI: 10.1371/journal.pntd.0003401] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 11/07/2014] [Indexed: 11/18/2022] Open
Abstract
The cyclooctadepsipeptide emodepside and its parent compound PF1022A are broad-spectrum nematicidal drugs which are able to eliminate nematodes resistant to other anthelmintics. The mode of action of cyclooctadepsipeptides is only partially understood, but involves the latrophilin Lat-1 receptor and the voltage- and calcium-activated potassium channel Slo-1. Genetic evidence suggests that emodepside exerts its anthelmintic activity predominantly through Slo-1. Indeed, slo-1 deficient Caenorhabditis elegans strains are completely emodepside resistant. However, direct effects of emodepside on Slo-1 have not been reported and these channels have only been characterized for C. elegans and related Strongylida. Molecular and bioinformatic analyses identified full-length Slo-1 cDNAs of Ascaris suum, Parascaris equorum, Toxocara canis, Dirofilaria immitis, Brugia malayi, Onchocerca gutturosa and Strongyloides ratti. Two paralogs were identified in the trichocephalids Trichuris muris, Trichuris suis and Trichinella spiralis. Several splice variants encoding truncated channels were identified in Trichuris spp. Slo-1 channels of trichocephalids form a monophyletic group, showing that duplication occurred after the divergence of Enoplea and Chromadorea. To explore the function of a representative protein, C. elegans Slo-1a was expressed in Xenopus laevis oocytes and studied in electrophysiological (voltage-clamp) experiments. Incubation of oocytes with 1-10 µM emodepside caused significantly increased currents over a wide range of step potentials in the absence of experimentally increased intracellular Ca2+, suggesting that emodepside directly opens C. elegans Slo-1a. Emodepside wash-out did not reverse the effect and the Slo-1 inhibitor verruculogen was only effective when applied before, but not after, emodepside. The identification of several splice variants and paralogs in some parasitic nematodes suggests that there are substantial differences in channel properties among species. Most importantly, this study showed for the first time that emodepside directly opens a Slo-1 channel, significantly improving the understanding of the mode of action of this drug class.
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Affiliation(s)
- Daniel Kulke
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
- Global Drug Discovery, Animal Health, Parasiticides, Bayer HealthCare, Leverkusen, Germany
| | | | - Sandra M. Miltsch
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
| | - Adrian J. Wolstenholme
- Department of Infectious Diseases, College of Veterinary Medicine, The University of Georgia, Athens, Georgia, United States of America
| | - Aaron R. Jex
- Faculty of Veterinary Science, The University of Melbourne, Parkville, Victoria, Australia
| | - Robin B. Gasser
- Faculty of Veterinary Science, The University of Melbourne, Parkville, Victoria, Australia
| | - Cristina Ballesteros
- Institute of Parasitology, McGill University, Sainte-Anne-de-Bellevue, Quebec, Canada
| | - Timothy G. Geary
- Institute of Parasitology, McGill University, Sainte-Anne-de-Bellevue, Quebec, Canada
| | - Jennifer Keiser
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Basel, Switzerland
| | - Simon Townson
- Tropical Parasitic Diseases Unit, Northwick Park Institute for Medical Research, Harrow, Middlesex, United Kingdom
| | - Achim Harder
- WE Biology, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Jürgen Krücken
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
- * E-mail:
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15
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Xie J. Differential evolution of signal-responsive RNA elements and upstream factors that control alternative splicing. Cell Mol Life Sci 2014; 71:4347-60. [PMID: 25064062 PMCID: PMC11113106 DOI: 10.1007/s00018-014-1688-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Revised: 07/13/2014] [Accepted: 07/17/2014] [Indexed: 12/17/2022]
Abstract
Cell signal-regulated alternative splicing occurs for many genes but the evolutionary origin of the regulatory components and their relationship remain unclear. This review focuses on the alternative splicing components of several systems based on the available bioinformatics data. Eight mammalian RNA elements for signal-regulated splicing were aligned among corresponding sequences from dozens of representative vertebrate species to allow for assessment of the trends in evolutionary changes. Four distinct trends were observed. Four of the elements are highly conserved in bird, reptile and fish species examined (i); two elements can be found in fish but the sequences have been changing till in marsupials or higher mammals (ii); one element is almost exclusively found in mammals with mostly the same sequence (iii); and one element can be found in birds or lower vertebrates but expanded abruptly to have variable numbers of copies in mammals (iv). All examined prototype trans-acting factors and protein kinases emerged earlier than the RNA elements but additional (paralog) factors emerged in the same or later species. Thus, after their emergence mainly in fish or mammals with pre-existing prototype trans-acting factors/kinases, half of the elements have been highly conserved from fish to humans but the other half have evolved differentially with additional trans-acting factors. Their differential evolution likely contributes to the exon- and species/class-specific control of alternative splicing and its regulation by cell signals. The evolvement of a group of mammal-specific components would help relay signals from extracellular stimuli to the splicing machinery and thus contribute to higher proteomic diversity.
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Affiliation(s)
- Jiuyong Xie
- Departments of Physiology, Biochemistry and Medical Genetics, Faculty of Medicine, University of Manitoba, Winnipeg, MB, R3E 0J9, Canada,
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16
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Rohmann KN, Tripp JA, Genova RM, Bass AH. Manipulation of BK channel expression is sufficient to alter auditory hair cell thresholds in larval zebrafish. ACTA ACUST UNITED AC 2014; 217:2531-9. [PMID: 24803460 DOI: 10.1242/jeb.103093] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Non-mammalian vertebrates rely on electrical resonance for frequency tuning in auditory hair cells. A key component of the resonance exhibited by these cells is an outward calcium-activated potassium current that flows through large-conductance calcium-activated potassium (BK) channels. Previous work in midshipman fish (Porichthys notatus) has shown that BK expression correlates with seasonal changes in hearing sensitivity and that pharmacologically blocking these channels replicates the natural decreases in sensitivity during the winter non-reproductive season. To test the hypothesis that reducing BK channel function is sufficient to change auditory thresholds in fish, morpholino oligonucleotides (MOs) were used in larval zebrafish (Danio rerio) to alter expression of slo1a and slo1b, duplicate genes coding for the pore-forming α-subunits of BK channels. Following MO injection, microphonic potentials were recorded from the inner ear of larvae. Quantitative real-time PCR was then used to determine the MO effect on slo1a and slo1b expression in these same fish. Knockdown of either slo1a or slo1b resulted in disrupted gene expression and increased auditory thresholds across the same range of frequencies of natural auditory plasticity observed in midshipman. We conclude that interference with the normal expression of individual slo1 genes is sufficient to increase auditory thresholds in zebrafish larvae and that changes in BK channel expression are a direct mechanism for regulation of peripheral hearing sensitivity among fishes.
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Affiliation(s)
- Kevin N Rohmann
- Department of Neurobiology and Behavior, Cornell University, Ithaca, New York, NY 14853, USA
| | - Joel A Tripp
- Department of Neurobiology and Behavior, Cornell University, Ithaca, New York, NY 14853, USA
| | - Rachel M Genova
- Department of Neurobiology and Behavior, Cornell University, Ithaca, New York, NY 14853, USA
| | - Andrew H Bass
- Department of Neurobiology and Behavior, Cornell University, Ithaca, New York, NY 14853, USA
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17
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Deem MW. Evolution: life has evolved to evolve: comment on "How life changes itself: the Read-Write (RW) genome" by James Shapiro. Phys Life Rev 2013; 10:333-5. [PMID: 23871431 DOI: 10.1016/j.plrev.2013.07.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Accepted: 07/04/2013] [Indexed: 12/14/2022]
Affiliation(s)
- Michael W Deem
- Department of Bioengineering, Department of Physics & Astronomy, Graduate Program in Systems, Synthetic, and Physical Biology, Rice University, Houston, TX 77005, USA.
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18
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Gall MD, Salameh TS, Lucas JR. Songbird frequency selectivity and temporal resolution vary with sex and season. Proc Biol Sci 2013. [PMID: 23193125 DOI: 10.1098/rspb.2012.2296] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Many species of songbirds exhibit dramatic seasonal variation in song output. Recent evidence suggests that seasonal changes in auditory processing are coincident with seasonal variation in vocal output. Here, we show, for the first time, that frequency selectivity and temporal resolution of the songbird auditory periphery change seasonally and in a sex-specific manner. Male and female house sparrows (Passer domesticus) did not differ in their frequency sensitivity during the non-breeding season, nor did they differ in their temporal resolution. By contrast, female house sparrows showed enhanced frequency selectivity during the breeding season, which was matched by a concomitant reduction of temporal resolution. However, males failed to show seasonal plasticity in either of these auditory properties. We discuss potential mechanisms generating these seasonal patterns and the implications of sex-specific seasonal changes in auditory processing for vocal communication.
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Affiliation(s)
- Megan D Gall
- Neuroscience Institute, Georgia State University, 100 Piedmont Avenue SE, Atlanta, GA 30303, USA.
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19
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Plasticity in ion channel expression underlies variation in hearing during reproductive cycles. Curr Biol 2013; 23:678-83. [PMID: 23562266 DOI: 10.1016/j.cub.2013.03.014] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2012] [Revised: 02/19/2013] [Accepted: 03/04/2013] [Indexed: 01/19/2023]
Abstract
Sensory plasticity related to reproductive state, hormonal profiles, and experience is widespread among vertebrates, including humans. Improvements in audio-vocal coupling that heighten the detection of conspecifics are part of the reproductive strategy of many nonmammalian vertebrates. Although seasonal changes in hearing are known, molecular mechanisms determining this form of adult sensory plasticity remain elusive. Among both nonmammals and mammals, large-conductance, calcium-activated potassium (BK) channels underlie a primary outward current having a predominant influence on frequency tuning in auditory hair cells. We now report an example from fish showing that increased BK channel abundance can improve an individual's ability to hear vocalizations during the breeding season. Pharmacological manipulations targeting BK channels, together with measures of BK transcript abundance, can explain the seasonal enhancement of auditory hair cell sensitivity to the frequency content of calls. Plasticity in ion channel expression is a simple, evolutionarily labile solution for sculpting sensory bandwidth to maximize the detection of conspecific signals during reproductive cycles.
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20
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Genova RM, Marchaterre MA, Knapp R, Fergus D, Bass AH. Glucocorticoid and androgen signaling pathways diverge between advertisement calling and non-calling fish. Horm Behav 2012; 62:426-32. [PMID: 22884426 DOI: 10.1016/j.yhbeh.2012.07.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2012] [Revised: 07/24/2012] [Accepted: 07/26/2012] [Indexed: 10/28/2022]
Abstract
Behavioral and neuroendocrine mechanisms of social vocalization in teleost fish are influenced by the glucocorticoid cortisol and the androgen 11-ketotestosterone (11kT). The relative abundance of both 11kT, which binds to androgen receptors (ARα, ARβ), and cortisol, which binds to glucocorticoid receptors (GR-1, GR-2), is regulated by 11β-hydroxylase (11βH) that converts 11-deoxycortisol to cortisol and testosterone to 11β-OH-testosterone, and 11β-hydroxysteroid dehydrogenase (11βHSD) that converts cortisol to the inactive metabolite cortisone and 11β-OH-testosterone to 11kT. In midshipman fish, we tested the hypothesis that plasma steroid levels, mRNA abundance for 11βH and 11βHSD in the vocal muscle and testis (known site of 11kT synthesis), and mRNA abundances for ARs and GRs in vocal muscle, would differ between males that did or did not recently produce 'hum' advertisement calls. Quantitative real-time PCR demonstrated that non-calling male vocal muscle had significantly higher mRNA levels for all receptors except ARα, and a strong trend for higher 11βHSD; 11βH was similar to that in calling males. Calling males had higher plasma and testis 11kT, but lower plasma cortisol, levels. Testis enzyme levels did not differ between male groups, although calling males showed a positive linear correlation between plasma 11kT and testis 11βHSD mRNA levels, consistent with testis being the main source of plasma 11kT. We propose that higher vocal muscle 11βHSD levels in non-calling males reflect increased local conversion of elevated cortisol to cortisone, providing protection from cortisol-related toxicity, while increased receptor expression in non-calling males functions as a preparatory mechanism for meeting the physiological demands of future vocalization.
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Affiliation(s)
- Rachel M Genova
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853, USA
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21
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Liu G, Razanau A, Hai Y, Yu J, Sohail M, Lobo VG, Chu J, Kung SKP, Xie J. A conserved serine of heterogeneous nuclear ribonucleoprotein L (hnRNP L) mediates depolarization-regulated alternative splicing of potassium channels. J Biol Chem 2012; 287:22709-16. [PMID: 22570490 DOI: 10.1074/jbc.m112.357343] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Molecular mechanisms of gene regulation underlying the activity-dependent long term changes of cellular electrical properties, such as those during memory, are largely unknown. We have shown that alternative splicing can be dynamically regulated in response to membrane depolarization and Ca(2+)/calmodulin-dependent protein kinase IV (CaMKIV) activation, through special CaM kinase responsive RNA elements. However, proteins that mediate this regulation and how they are affected by CaMKIV are not known. Here we show that the regulation of the stress axis-regulated exon of the Slo1 potassium channel transcripts by membrane depolarization requires a highly conserved CaMKIV target serine (Ser-513) of the heterogeneous ribonucleoprotein L. Ser-513 phosphorylation within the RNA recognition motif 4 enhanced heterogeneous ribonucleoprotein L interaction with the CaMKIV-responsive RNA element 1 of stress axis-regulated exon and inhibited binding of the large subunit of the U2 auxiliary factor U2AF65. Both of these activities were abolished by a S513A mutation. Thus, through Ser-513, membrane depolarization/calcium signaling controls a critical spliceosomal assembly step to regulate the variant subunit composition of potassium channels.
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Affiliation(s)
- Guodong Liu
- Department of Physiology, Faculty of Medicine, University of Manitoba, 745 Bannatyne Ave., Winnipeg, MB R3E 0J9, Canada
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22
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Saccular-specific hair cell addition correlates with reproductive state-dependent changes in the auditory saccular sensitivity of a vocal fish. J Neurosci 2012; 32:1366-76. [PMID: 22279221 DOI: 10.1523/jneurosci.4928-11.2012] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
The plainfin midshipman fish, Porichthys notatus, is a seasonal breeding teleost fish for which vocal-acoustic communication is essential for its reproductive success. Female midshipman use the saccule as the primary end organ for hearing to detect and locate "singing" males that produce multiharmonic advertisement calls during the summer breeding season. Previous work has shown that female auditory sensitivity changes seasonally with reproductive state; summer reproductive females become better suited than winter nonreproductive females to detect and encode the dominant higher harmonic components in the male's advertisement call, which are potentially critical for mate selection and localization. Here, we test the hypothesis that these seasonal changes in female auditory sensitivity are concurrent with seasonal increases in saccular hair cell receptors. We show that there is increased hair cell density in reproductive females and that this increase is not dependent on body size since similar changes in hair cell density were not found in the other inner ear end organs. We also observed an increase in the number of small, potentially immature saccular hair bundles in reproductive females. The seasonal increase in saccular hair cell density and smaller hair bundles in reproductive females was paralleled by a dramatic increase in the magnitude of the evoked saccular potentials and a corresponding decrease in the auditory thresholds recorded from the saccule. This demonstration of correlated seasonal plasticity of hair cell addition and auditory sensitivity may in part facilitate the adaptive auditory plasticity of this species to enhance mate detection and localization during breeding.
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Rohmann KN, Bass AH. Seasonal plasticity of auditory hair cell frequency sensitivity correlates with plasma steroid levels in vocal fish. J Exp Biol 2011; 214:1931-42. [PMID: 21562181 PMCID: PMC3092729 DOI: 10.1242/jeb.054114] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/18/2011] [Indexed: 01/14/2023]
Abstract
Vertebrates displaying seasonal shifts in reproductive behavior provide the opportunity to investigate bidirectional plasticity in sensory function. The midshipman teleost fish exhibits steroid-dependent plasticity in frequency encoding by eighth nerve auditory afferents. In this study, evoked potentials were recorded in vivo from the saccule, the main auditory division of the inner ear of most teleosts, to test the hypothesis that males and females exhibit seasonal changes in hair cell physiology in relation to seasonal changes in plasma levels of steroids. Thresholds across the predominant frequency range of natural vocalizations were significantly less in both sexes in reproductive compared with non-reproductive conditions, with differences greatest at frequencies corresponding to call upper harmonics. A subset of non-reproductive males exhibiting an intermediate saccular phenotype had elevated testosterone levels, supporting the hypothesis that rising steroid levels induce non-reproductive to reproductive transitions in saccular physiology. We propose that elevated levels of steroids act via long-term (days to weeks) signaling pathways to upregulate ion channel expression generating higher resonant frequencies characteristic of non-mammalian auditory hair cells, thereby lowering acoustic thresholds.
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Affiliation(s)
- Kevin N Rohmann
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14854, USA.
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