Abstract
The teneurins (Ten-m/Odz) are a family of evolutionarily ancient transmembrane molecules whose complex and multi-faceted roles in the generation of mammalian neural circuits are only beginning to be appreciated. In mammals there are four family members (Ten-m1-4). Initial expression studies in vertebrates revealed intriguing expression patterns in interconnected populations of neurons. These observations, together with biochemical and over-expression studies, led to the hypothesis that homophilic interactions between teneurins on afferent and target cells may help to guide the assembly of neural circuits. This review will focus on insights gained on teneurin function in vivo in mammals using mouse knockout models. These studies provide support for the hypothesis that homophilic interactions between teneurin molecules can guide the formation of neural connections with largely consistent results obtained in hippocampal and striatal circuits. Mapping changes obtained in the mouse visual pathway, however, suggest additional roles for these glycoproteins in the formation and specification of circuits which subserve binocular vision.
Introduction
The idea that groups of afferent and target neurons positioned at locations remote from each other could set up precise, ordered patterns of connectivity due to the affinity of chemicals expressed on or by these cells was postulated formally by Roger Sperry in his chemoaffinity hypothesis (). Over the last few decades, a few families of molecules that exhibit expression patterns which fit largely with his predictions have been identified, with notable examples including the Ephs/ephrins, cadherin and immunoglobulin superfamilies (; ). One of the more recent entrants to this stage is the teneurins. In a range of different species and brain circuits, these molecules were found to exhibit distributions across afferent and target fields which pointed to the idea that they may indeed help to determine patterns of neural connectivity (e.g., , ; ; ; ; , ; ; ). Over recent years, genetically modified mice have been generated which have enabled these ideas to be tested in vivo. The focus of this article is to review what has been learnt from these studies. As will be discussed below, they show key roles for teneurin molecules in regulating the patterns of connectivity in multiple neural circuits, including visual, hippocampal, and striatal networks. Compelling evidence that homophilic interactions between teneurins on axons and targets help to specify precise patterns of connectivity will be described. Evidence that teneurins also play other important roles in mediating appropriate wiring and synaptic efficacy, including interactions with, and regulation of the expression of other molecules will also be presented.
Topographically Corresponding Gradients Mediate Precise Matching of Neural Connections Via Homophilic Interactions
Teneurins exhibit differential expression patterns within neural circuits. In the chick visual system, for example, Ten-m1 and Ten-m2 were found to be differentially expressed by the tectofugal and thalamofugal pathways, respectively (, ). Dynamic and differential, but partially overlapping, expression patterns have also been observed in the nervous system of zebrafish, with particularly strong expression of Ten-m3 and Ten-m4 (; ). In this species, expression of Ten-m3 in the amacrine and ganglion cells of the developing retina is important for the formation of intraretinal circuitry (, ). In addition to different Ten-ms being selectively expressed by specific pathways, topographically corresponding gradients of expression have also been observed at multiple levels within given circuits, suggesting a role in generating precise patterns of connectivity between remotely located afferent and target fields. The most notable examples of this are the expression patterns of Ten-m3 in the developing visual, hippocampal, and striatal circuits in mice.
Initial descriptions of the expression patterns of teneurins in the cortex of the mouse described high levels of Ten-m2, Ten-m3, and Ten-m4 in caudal regions of cortex, with Ten-m1 expressed in more rostral areas (; ). Expression in the caudal domain included the primary visual cortex, multiple subregions of the hippocampus and associated cortical areas, as well as intriguing expression patterns in the thalamus and striatum (; ; ; ; ).
While both Ten-m2 and Ten-m4 displayed fairly uniform expression across given subregions of the hippocampus, Ten-m3 showed evidence of differential expression within these areas (; ; ). Recent work has confirmed the presence of a gradient of Ten-m3 across three interconnected regions: CA1, subiculum, and entorhinal cortex (). Further, the gradients of Ten-m3 are topographically aligned across these regions: medial entorhinal cortex, proximal CA1, and distal subiculum, all express high levels of Ten-m3 (Figure 1A), and are connected to each other. In contrast, the lateral entorhinal cortex, distal CA1, and proximal subiculum circuit are similarly interconnected and all exhibit low levels of Ten-m3 expression (). Further, this paper showed that multiple other interconnected regions of the hippocampal circuit including the mammillary bodies, anteroventral thalamic nucleus, and pre- as well as para-subiculum also display gradients of Ten-m3 (; ).
FIGURE 1
A topographic correspondence in the expression patterns of Ten-m3 between connected areas has also been found for the thalamostriatal pathway (
The observation of a high caudal to low rostral expression gradient across the visual cortex (
FIGURE 2

Deletion of Ten-m3 and Ten-m2 lead to specific, complementary wiring deficits within the retinogeniculate pathway. (A,B) Ten-m3 exhibits a high dorsomedial to a low ventrolateral gradient in coronal sections of the dLGN complimenting the high ventral, low dorsal expression gradient present in the retina (A). In contrast, Ten-m2 exhibits a uniform expression pattern across both the retina and dLGN (B). Binocular retinal projections from the VTC (gray outline) target complimentary, topographically aligned regions within the dLGN of both Ten-m2 and Ten-m3 WTs. (C) Ten-m3 deletion results in a dramatic miswiring of ipsilateral retinal projections, with aberrant terminals targeting the normally monocular ventrolateral region of the nucleus. Contralateral projections remain largely unaltered, leading to a disruption of the topographical overlap between the inputs from both eyes. (D) Removal of Ten-m2, in contrast, results in ipsilateral projections from the ventral portion of the VTC taking on a contralateral fate, effectively reducing the size of both the VTC and the ipsilateral recipient area within the dLGN. Thus, Ten-m2 is required for appropriate guidance at the optic chiasm, whereas Ten-m3 is required for appropriate topographic mapping with target structures (based on
The remarkable consistency in these patterns within a range of neural circuits across Mammalia pointed strongly to the idea that Ten-m3 may function as a classic chemoaffinity molecule, promoting connectivity between afferent axons and target cells with corresponding levels of expression. While in vitro studies have provided general support for this idea, showing that teneurins promote cellular adhesion in vitro (
Analysis of the Ten-m3 knockout mouse, generated by deletion of exon 4 (
Several questions remain unanswered, however. Most notably, is Ten-m3 expression required in afferent axons, target cells, or both? The recent development of a conditional Ten-m3 KO mouse has enabled this issue to be elegantly addressed in the hippocampal circuit. Deletion of Ten-m3 in either the afferent or the target cells alone is sufficient to disrupt the usual pattern of connectivity between CA1 and subiculum (
Beyond Homophilic Adhesion: Teneurins in the Formation of Binocular Visual Circuits
The studies described above provide compelling evidence that the graded expression pattern of Ten-m3 is fundamentally important in promoting precise patterns of connectivity within neural circuits, supporting its role as a homophilic adhesion molecule. Evidence suggests, however, that this may be only one component of Ten-m3’s function, at least for the formation of binocular visual circuits.
As noted above, topographically connected regions of the early visual pathway show similar expression levels of Ten-m3. Evidence of altered mapping is apparent in the contralateral retinocollicular pathway of Ten-m3 KOs (
Since the ipsilateral projection arises from, and projects to, regions associated with high levels of Ten-m3 expression, the changes observed in KOs are broadly consistent with the idea that this molecule promotes the formation of synaptic contacts between areas with similar expression levels, and thus helps to set up topographical alignment within the visual pathway. A critical look, however, suggests a more complex role. Notably, the expression of Ten-m3 has a broad ventrodorsal retinal gradient, but shows no difference between temporal and nasal regions (
An investigation into the development of the retinogeniculate projection revealed that the mistargeting of ipsilateral RGC terminals in the dLGN in Ten-m3 KOs is preceded by an abnormally early exit of retinal axons from the optic tract into the nucleus (
Interestingly, since Zic2 and EphB1 promote ipsilateral identity and retinal axon guidance, respectively (
As noted above, two other members of the Teneurin family, Ten-m2 and Ten-m4, are also highly expressed in the mouse visual cortex at around the time of birth (
Functional Impacts From Loss of Teneurin Function
The impact of the loss of teneurin function on behavior in KO mice has been best characterized for the visual pathway. In Ten-m3 KOs, the mistargeting of ipsilateral retinal axons is associated with profound visual deficits. Assessment of behavior that requires patterned vision reveals performance at chance levels, although the mice show an ability to distinguish between dark and light (
While the Ten-ms clearly play an important role in the formation of binocular visual circuits in mice, it should be pointed out that they are also expressed in the visual pathway of zebrafish and chicks (
The impaired thalamostriatal targeting in Ten-m3 KOs is also associated with functional changes. Notably, while there is no difference in initial and post-acquisition performance levels of a simple motor task, the rate of learning is negatively affected in Ten-m3 KOs (
Ten-m1 is highly expressed in the olfactory bulb and cortex (Allen Brain Atlas). Deletion of Ten-m1 has been shown to affect the KOs ability to detect appetitive and aversive odors (
While a thorough behavioral characterization has yet to be conducted on Ten-m4 KOs, this teneurin has been linked to bipolar disorder and schizophrenia in humans (
Concluding Remarks
These studies reviewed above demonstrate multiple, complex and important roles for teneurins in the formation and function of neural circuits. Their ability to mediate homophilic interactions is clearly crucial for the formation of precisely mapped connections between afferent and target fields in these circuits. Each of the teneurins, however, contains multiple domains and cleavage sites that may allow these molecules to also undergo heterophilic interactions with other key signaling molecules, such as the latrophilins (
Statements
Author contributions
Both authors contributed to the writing and editing of this manuscript.
Conflict of interest
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
References
1
AldahmeshM. A.MohammedJ. Y.Al-HazzaaS.AlkuruyaF. S. (2012). Homozygous null mutation in Odz3 causes micropthalmia in humans.Genet. Med.14900–904. 10.1038/gim.2012.71
2
AlkelaiA.OlenderT.Haffner-KrauszR.TsooryM. M.BoykoV.TatarskyyP. (2016). A role for TENM1 mutations in congenital general anosmia.Clin. Genet.90211–219. 10.1111/cge.12782
3
AntinucciP.NikolaouN.MeyerM. P.HindgesR. (2013). Teneurin-3 specifies morphological and functional connectivity of retinal ganglion cells in the vertebrate visual system.Cell Rep.5582–592. 10.1016/j.celrep.2013.09.045
4
AntinucciP.SuleymanO.MonfriesC.HindgesR. (2016). Neural mechanisms generating orientation selectivity in the retina.Curr. Biol.261802–1815. 10.1016/j.cub.2016.05.035
5
BaguttiC.ForroG.FerralliJ.RubinB.Chiquet-EhrismannR. (2003). The intracellular domain of teneurin-2 has a nuclear function and represses zic-1-mediated transcription.J. Cell Sci.116(Pt 14), 2957–2966. 10.1242/jcs.00603
6
BernsD. S.DeNardoL. A.PederickD. T.LuoL. (2018). Teneurin-3 controls topographic circuit assembly in the hippocampus.Nature554328–333. 10.1038/nature25463
7
Bibollet-BahenaO.OkafujiT.HokampK.TearG.MitchellK. J. (2017). A dual-strategy expression screen for candidate connectivity labels in the developing thalamus.PLoS One12:e0177977. 10.1371/journal.pone.0177977
8
BoucardA. A.MaxeinerS.SudhofT. C. (2014). Latrophilins function as heterophilic cell-adhesion molecules by binding to teneurins: regulation by alternative splicing.J. Biol. Chem.289387–402. 10.1074/jbc.M113.504779
9
CarrO. P.GlendiningK. A.LeameyC. A.MarotteL. R. (2013). Overexpression of Ten-m3 in the retina alters ipsilateral retinocollicular projections in the wallaby (Macropus eugenii).Int. J. Dev. Neurosci.31496–504. 10.1016/j.ijdevneu.2013.05.011
10
CarrO. P.GlendiningK. A.LeameyC. A.MarotteL. R. (2014). Retinal overexpression of Ten-m3 alters ipsilateral retinogeniculate projections in the wallaby (Macropus eugenii).Neurosci. Lett.566C167–171. 10.1016/j.neulet.2014.02.048
11
CheungA.TreversK. E.Reyes CorralM.AntinucciP.HindgesR. (2019). Expression and roles of teneurins in zebrafish.Front. Neurosci.13:158. 10.3389/fnins.2019.00158
12
DharmaratneN.GlendiningK. A.YoungT. R.TranH.SawatariA.LeameyC. A. (2012). Ten-m3 is required for the development of topography in the ipsilateral retinocollicular pathway.PLoS One7:e43083. 10.1371/journal.pone.0043083
13
DragerU. C.OlsenJ. F. (1980). Origins of crossed and uncrossed retinal projections in pigmented and albino mice.J. Comp. Neurol.191383–412. 10.1002/cne.901910306
14
FeldheimD. A.KimY. I.BergemannA. D.FrisenJ.BarbacidM.FlanaganJ. G. (2000). Genetic analysis of ephrin-A2 and ephrin-A5 shows their requirement in multiple aspects of retinocollicular mapping.Neuron25563–574. 10.1016/s0896-6273(00)81060-0
15
FeldheimD. A.VanderhaeghenP.HansenM. J.FrisenJ.LuQ.BarbacidM.et al (1998). Topographic guidance labels in a sensory projection to the forebrain.Neuron211303–1313. 10.1016/s0896-6273(00)80650-9
16
FrisenJ.YatesP. A.McLaughlinT.FriedmanG. C.O’LearyD. D.BarbacidM. (1998). Ephrin-A5 (AL-1/RAGS) is essential for proper retinal axon guidance and topographic mapping in the mammalian visual system.Neuron20235–243. 10.1016/s0896-6273(00)80452-3
17
Garcia-FrigolaC.CarreresM. I.VegarC.HerreraE. (2008). Zic2 promotes axonal divergence at the optic chiasm by EphB1-dependent andd independent mechanisms.Development1351833–1841. 10.1242/dev.020693
18
GlendiningK. A.LiuS. C.NguyenM.DharmaratneN.NagarajahR.IglesiasM. A.et al (2017). Downstream mediators of Ten-m3 signalling in the developing visual pathway.BMC Neurosci.18:78. 10.1186/s12868-017-0397-5
19
HeinrichA.LourdusamyA.TzschoppeJ.Vollstadt-KleinS.BuhlerM.SteinerS. (2013). The risk variant in ODZ4 for bipolar disorder impacts on amygdala activation during reward processing.Bipolar Disord.15440–445. 10.1111/bdi.12068
20
HerreraE.BrownL.ArugaJ.RachelR. A.DolenG.MikoshibaK.et al (2003). Zic2 patterns binocular vision by specifying the uncrossed retinal projection.Cell114545–557. 10.1016/s0092-8674(03)00684-6
21
HindgesR.McLaughlinT.GenoudN.HenkemeyerM.O’LearyD. D. (2002). EphB forward signaling controls directional branch extension and arborization required for dorsal-ventral retinotopic mapping.Neuron35475–487. 10.1016/s0896-6273(02)00799-7
22
HongW.MoscaT. J.LuoL. (2012). Teneurins instruct synaptic partner matching in an olfactory map.Nature484201–207. 10.1038/nature10926
23
HorH.FrancescattoL.BartesaghiL.Ortega-CuberoS.KousiM.Lorenzo-BetancorO. (2015). Missense mutations in TENM4, a regulator of axon guidance and central myelination, cause essential tremor.Hum. Mol. Genet.245677–5686. 10.1093/hmg/ddv281
24
IvorraJ. L.RiveroO.CostasJ.IniestaR.ArrojoM.Ramos-RiosR. (2014). Replication of previous genome-wide association studies of psychiatric diseases in a large schizophrenia case-control sample from Spain.Schizophr. Res.159107–113. 10.1016/j.schres.2014.07.004
25
LeameyC. A.GlendiningK. A.KreimanG.KangN. D.WangK. H.FasslerR. (2008). Differential gene expression between sensory neocortical areas: potential roles for Ten_m3 and Bcl6 in patterning visual and somatosensory pathways.Cereb. Cortex1853–66. 10.1093/cercor/bhm031
26
LeameyC. A.MerlinS.LattoufP.SawatariA.ZhouX.DemelN. (2007). Ten_m3 regulates eye-specific patterning in the mammalian visual pathway and is required for binocular vision.PLoS Biol.5:e241. 10.1371/journal.pbio.0050241
27
LeameyC. A.SawatariA. (2014). The teneurins: new players in the generation of visual topography.Semin. Cell Dev. Biol.35173–179. 10.1016/j.semcdb.2014.08.007
28
LeeR.PetrosT. J.MasonC. A. (2008). Zic2 regulates retinal ganglion cell axon avoidance of ephrinB2 through inducing expression of the guidance receptor EphB1.J. Neurosci.285910–5919. 10.1523/JNEUROSCI.0632-08.2008
29
LiH.BishopK. M.O’LearyD. D. (2006). Potential target genes of EMX2 include Odz/Ten-M and other gene families with implications for cortical patterning.Mol. Cell. Neurosci.33136–149. 10.1016/j.mcn.2006.06.012
30
McLaughlinT.HindgesR.YatesP. A.O’LearyD. D. (2003). Bifunctional action of ephrin-B1 as a repellent and attractant to control bidirectional branch extension in dorsal-ventral retinotopic mapping.Development1302407–2418. 10.1242/dev.00467
31
McLaughlinT.O’LearyD. D. (2005). Molecular gradients and development of retinotopic maps.Annu. Rev. Neurosci.28327–355. 10.1146/annurev.neuro.28.061604.135714
32
MerlinS.HorngS.MarotteL. R.SurM.SawatariA.LeameyC. A. (2013). Deletion of Ten-m3 induces the formation of eye dominance domains in mouse visual cortex.Cereb. Cortex23763–774. 10.1093/cercor/bhs030
33
MiedaM.KikuchiY.HirateY.AokiM.OkamotoH. (1999). Compartmentalized expression of zebrafish ten-m3 and ten-m4, homologues of the Drosophila ten(m)/odd Oz gene, in the central nervous system.Mech. Dev.87223–227. 10.1016/s0925-4773(99)00155-0
34
PfeiffenbergerC.CutforthT.WoodsG.YamadaJ.RenteriaR. C.CopenhagenD. R.et al (2005). Ephrin-As and neural activity are required for eye-specific patterning during retinogeniculate mapping.Nat. Neurosci.81022–1027. 10.1038/nn1508
35
RubinB. P.TuckerR. P.Brown-LuediM.MartinD.Chiquet-EhrismannR. (2002). Teneurin 2 is expressed by the neurons of the thalamofugal visual system in situ and promotes homophilic cell-cell adhesion in vitro.Development1294697–4705.
36
RubinB. P.TuckerR. P.MartinD.Chiquet-EhrismannR. (1999). Teneurins: a novel family of neuronal cell surface proteins in vertebrates, homologous to the Drosophila pair-rule gene product Ten-m.Dev. Biol.216195–209. 10.1006/dbio.1999.9503
37
SandoR.JiangX.SudhofT. C. (2019). Latrophilin GPCRs direct synapse specificity by coincident binding of FLRTs and teneurins.Science363:6429. 10.1126/science.aav7969
38
SperryR. W. (1963). Chemoaffinity in the orderly growth of nerve fiber patterns and connections.Proc. Natl. Acad. Sci. U.S.A.50703–710. 10.1073/pnas.50.4.703
39
SuzukiN.FukushiM.KosakiK.DoyleA. D.de VegaS.YoshizakiK. (2012). Teneurin-4 is a novel regulator of oligodendrocyte differentiation and myelination of small-diameter axons in the CNS.J. Neurosci.3211586–11599. 10.1523/JNEUROSCI.2045-11.2012
40
TranH.SawatariA.LeameyC. A. (2015). The glycoprotein Ten-m3 mediates topography and patterning of thalamostriatal projections from the parafascicular nucleus in mice.Eur. J. Neurosci.4155–68. 10.1111/ejn.12767
41
TuckerR. P.BeckmannJ.LeachmanN. T.ScholerJ.Chiquet-EhrismannR. (2012). Phylogenetic analysis of the teneurins: conserved features and premetazoan ancestry.Mol. Biol. Evol.291019–1029. 10.1093/molbev/msr271
42
VysokovN. V.SilvaJ. P.LelianovaV. G.HoC.DjamgozM. B.TonevitskyA. G.et al (2016). The Mechanism of Regulated Release of Lasso/Teneurin-2.Front. Mol. Neurosci.9:59. 10.3389/fnmol.2016.00059
43
VysokovN. V.SilvaJ. P.LelianovaV. G.SucklingJ.CassidyJ.BlackburnJ. K. (2018). Proteolytically released Lasso/teneurin-2 induces axonal attraction by interacting with latrophilin-1 on axonal growth cones.eLife7:e37935. 10.7554/eLife.37935
44
WilliamsS. E.MannF.ErskineL.SakuraiT.WeiS.RossiD. J.et al (2003). Ephrin-B2 and EphB1 mediate retinal axon divergence at the optic chiasm.Neuron39919–935. 10.1016/j.neuron.2003.08.017
45
YoungT. R.BourkeM.ZhouX.OohashiT.SawatariA.FasslerR. L.et al (2013). Ten-m2 is required for the generation of binocular visual circuits.J. Neurosci.3312490–12509. 10.1523/JNEUROSCI.4708-12.2013
46
ZhouX. H.BrandauO.FengK.OohashiT.NinomiyaY.RauchU.et al (2003). “The murine Ten-m/Odz genes show distinct but overlapping expression patterns during development and in adult brain”.Gene Expr. Patt.3397–405. 10.1016/s1567-133x(03)00087-5
47
ZipurskyS. L.SanesJ. R. (2010). Chemoaffinity revisited: dscams, protocadherins, and neural circuit assembly.Cell143343–353. 10.1016/j.cell.2010.10.009
Summary
Keywords
Ten-m/Odz/teneurin, visual pathway, chemoaffinity, development, hippocampus, striatum, neural circuits
Citation
Leamey CA and Sawatari A (2019) Teneurins: Mediators of Complex Neural Circuit Assembly in Mammals. Front. Neurosci. 13:580. doi: 10.3389/fnins.2019.00580
Received
22 March 2019
Accepted
22 May 2019
Published
05 June 2019
Volume
13 - 2019
Edited by
Richard P. Tucker, University of California, Davis, United States
Reviewed by
Robert Hindges, King’s College London, United Kingdom; Timothy Mosca, Thomas Jefferson University, United States
Updates

Check for updates
Copyright
© 2019 Leamey and Sawatari.
This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
*Correspondence: Catherine A. Leamey, catherine.leamey@sydney.edu.au
This article was submitted to Neuroendocrine Science, a section of the journal Frontiers in Neuroscience
Disclaimer
All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.