Zebrafish Mnx proteins specify one motoneuron subtype and suppress acquisition of interneuron characteristics

Neural Development

Judith S Eisen²  Sarah A Hutchinson¹  Liesl Van Ryswyk²  Steve D Seredick² 

[1] Current address: Program in Developmental & Stem Cell Biology, The Hospital for Sick Children, 101 College Street, MaRS East Tower, Room 11-601, Toronto, ON, M5G 1L7, Canada;Institute of Neuroscience, 1254 University of Oregon, Eugene, OR, 97403, USA

关键词: Interneuron;    Motoneuron;    Mnx;    Zebrafish;   

Others  :  806887
DOI  :  10.1186/1749-8104-7-35

 received in 2012-08-31, accepted in 2012-10-16,  发布年份 2012

【 摘 要 】

Background

Precise matching between motoneuron subtypes and the muscles they innervate is a prerequisite for normal behavior. Motoneuron subtype identity is specified by the combination of transcription factors expressed by the cell during its differentiation. Here we investigate the roles of Mnx family transcription factors in specifying the subtypes of individually identified zebrafish primary motoneurons.

Results

Zebrafish has three Mnx family members. We show that each of them has a distinct and temporally dynamic expression pattern in each primary motoneuron subtype. We also show that two Mnx family members are expressed in identified VeLD interneurons derived from the same progenitor domain that generates primary motoneurons. Surprisingly, we found that Mnx proteins appear unnecessary for differentiation of VeLD interneurons or the CaP motoneuron subtype. Mnx proteins are, however, required for differentiation of the MiP motoneuron subtype. We previously showed that MiPs require two temporally-distinct phases of Islet1 expression for normal development. Here we show that in the absence of Mnx proteins, the later phase of Islet1 expression is initiated but not sustained, and MiPs become hybrids that co-express morphological and molecular features of motoneurons and V2a interneurons. Unexpectedly, these hybrid MiPs often extend CaP-like axons, and some MiPs appear to be entirely transformed to a CaP morphology.

Conclusions

Our results suggest that Mnx proteins promote MiP subtype identity by suppressing both interneuron development and CaP axon pathfinding. This is, to our knowledge, the first report of transcription factors that act to distinguish CaP and MiP subtype identities. Our results also suggest that MiP motoneurons are more similar to V2 interneurons than are CaP motoneurons.

【 授权许可】

   
2012 Seredick et al.; licensee BioMed Central Ltd.

【 图 表 】

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【 参考文献 】

• [1]Lewis KE, Eisen JS: From cells to circuits: development of the zebrafish spinal cord. Prog Neurobiol 2003, 69:419-449.
• [2]Shirasaki R, Pfaff SL: Transcriptional codes and the control of neuronal identity. Annu Rev Neurosci 2002, 25:251-281.
• [3]Alaynick WA, Jessell TM, Pfaff SL: SnapShot: spinal cord development. Cell 2011, 146:178. 178.e1
• [4]Park HC, Shin J, Appel B: Spatial and temporal regulation of ventral spinal cord precursor specification by Hedgehog signaling. Development 2004, 131:5959-5969.
• [5]Eisen JS, Myers PZ, Westerfield M: Pathway selection by growth cones of identified motoneurones in live zebra fish embryos. Nature 1986, 320:269-271.
• [6]Eisen JS, Pike SH, Romancier B: An identified motoneuron with variable fates in embryonic zebrafish. J Neurosci 1990, 10:34-43.
• [7]Eisen JS, Melancon E: Interactions with identified muscle cells break motoneuron equivalence in embryonic zebrafish. Nat Neurosci 2001, 4:1065-1070.
• [8]Hutchinson SA, Eisen JS: Islet1 and Islet2 have equivalent abilities to promote motoneuron formation and to specify motoneuron subtype identity. Development 2006, 133:2137-2147.
• [9]Appel B, Korzh V, Glasgow E, Thor S, Edlund T, Dawid IB, Eisen JS: Motoneuron fate specification revealed by patterned LIM homeobox gene expression in embryonic zebrafish. Development 1995, 121:4117-4125.
• [10]Hutchinson SA, Cheesman SE, Hale LA, Boone JQ, Eisen JS: Nkx6 proteins specify one zebrafish primary motoneuron subtype by regulating late islet1 expression. Development 2007, 134:1671-1677.
• [11]Melancon E, Liu DW, Westerfield M, Eisen JS: Pathfinding by identified zebrafish motoneurons in the absence of muscle pioneers. J Neurosci 1997, 17:7796-7804.
• [12]Kimura Y, Okamura Y, Higashijima S: Alx, a zebrafish homolog of Chx10, marks ipsilateral descending excitatory interneurons that participate in the regulation of spinal locomotor circuits. J Neurosci 2006, 26:5684-5697.
• [13]Kimura Y, Satou C, Higashijima S: V2a and V2b neurons are generated by the final divisions of pair-producing progenitors in the zebrafish spinal cord. Development 2008, 135:3001-3005.
• [14]Ferrier DE, Brooke NM, Panopoulou G, Holland PW: The Mnx homeobox gene class defined by HB9, MNR2 and amphioxus AmphiMnx. Dev Genes Evol 2001, 211:103-107.
• [15]Tanabe Y, William C, Jessell TM: Specification of motor neuron identity by the MNR2 homeodomain protein. Cell 1998, 95:67-80.
• [16]Arber S, Han B, Mendelsohn M, Smith M, Jessell TM, Sockanathan S: Requirement for the homeobox gene Hb9 in the consolidation of motor neuron identity. Neuron 1999, 23:659-674.
• [17]Thaler J, Harrison K, Sharma K, Lettieri K, Kehrl J, Pfaff SL: Active suppression of interneuron programs within developing motor neurons revealed by analysis of homeodomain factor HB9. Neuron 1999, 23:675-687.
• [18]Eisen JS: A case of mistaken identity. Neuron 1999, 23:626-627.
• [19]Brownstone RM, Wilson JM: Strategies for delineating spinal locomotor rhythm-generating networks and the possible role of Hb9 interneurones in rhythmogenesis. Brain Res Rev 2008, 57:64-76.
• [20]Wendik B, Maier E, Meyer D: Zebrafish mnx genes in endocrine and exocrine pancreas formation. Dev Biol 2004, 268:372-383.
• [21]Eisen JS, Smith JC: Controlling morpholino experiments: don't stop making antisense. Development 2008, 135:1735-1743.
• [22]Inoue A, Takahashi M, Hatta K, Hotta Y, Okamoto H: Developmental regulation of islet-1 mRNA expression during neuronal differentiation in embryonic zebrafish. Dev Dyn 1994, 199:1-11.
• [23]Korzh V, Edlund T, Thor S: Zebrafish primary neurons initiate expression of the LIM homeodomain protein Isl-1 at the end of gastrulation. Development 1993, 118:417-425.
• [24]Bernhardt RR, Chitnis AB, Lindamer L, Kuwada JY: Identification of spinal neurons in the embryonic and larval zebrafish. J Comp Neurol 1990, 302:603-616.
• [25]Eisen JS: Determination of primary motoneuron identity in developing zebrafish embryos. Science 1991, 252:569-572.
• [26]Eisen JS, Pike SH: The spt-1 mutation alters segmental arrangement and axonal development of identified neurons in the spinal cord of the embryonic zebrafish. Neuron 1991, 6:767-776.
• [27]Bernhardt RR, Patel CK, Wilson SW, Kuwada JY: Axonal trajectories and distribution of GABAergic spinal neurons in wildtype and mutant zebrafish lacking floor plate cells. J Comp Neurol 1992, 326:263-272.
• [28]Higashijima S, Mandel G, Fetcho JR: Distribution of prospective glutamatergic, glycinergic, and GABAergic neurons in embryonic and larval zebrafish. J Comp Neurol 2004, 480:1-18.
• [29]Batista MF, Jacobstein J, Lewis KE: Zebrafish V2 cells develop into excitatory CiD and Notch signalling dependent inhibitory VeLD interneurons. Dev Biol 2008, 322:263-275.
• [30]Myers PZ, Eisen JS, Westerfield M: Development and axonal outgrowth of identified motoneurons in the zebrafish. J Neurosci 1986, 6:2278-2289.
• [31]Park HC, Mehta A, Richardson JS, Appel B: Olig2 is required for zebrafish primary motor neuron and oligodendrocyte development. Dev Biol 2002, 248:356-368.
• [32]Lee S, Lee B, Joshi K, Pfaff SL, Lee JW, Lee SK: A regulatory network to segregate the identity of neuronal subtypes. Dev Cell 2008, 14:877-889.
• [33]Thaler JP, Lee SK, Jurata LW, Gill GN, Pfaff SL: LIM factor Lhx3 contributes to the specification of motor neuron and interneuron identity through cell-type-specific protein-protein interactions. Cell 2002, 110:237-249.
• [34]William CM, Tanabe Y, Jessell TM: Regulation of motor neuron subtype identity by repressor activity of Mnx class homeodomain proteins. Development 2003, 130:1523-1536.
• [35]Tallafuss A, Eisen JS: The Met receptor tyrosine kinase prevents zebrafish primary motoneurons from expressing an incorrect neurotransmitter. Neural Dev 2008, 3:18. BioMed Central Full Text
• [36]Sato-Maeda M, Obinata M, Shoji W: Position fine-tuning of caudal primary motoneurons in the zebrafish spinal cord. Development 2008, 135:323-332.
• [37]Higashijima S, Schaefer M, Fetcho JR: Neurotransmitter properties of spinal interneurons in embryonic and larval zebrafish. J Comp Neurol 2004, 480:19-37.
• [38]Odden JP, Holbrook S, Doe CQ: Drosophila HB9 is expressed in a subset of motoneurons and interneurons, where it regulates gene expression and axon pathfinding. J Neurosci 2002, 22:9143-9149.
• [39]Broihier HT, Skeath JB: Drosophila homeodomain protein dHb9 directs neuronal fate via crossrepressive and cell-nonautonomous mechanisms. Neuron 2002, 35:39-50.
• [40]Kwan AC, Dietz SB, Webb WW, Harris-Warrick RM: Activity of Hb9 interneurons during fictive locomotion in mouse spinal cord. J Neurosci 2009, 29:11601-11613.
• [41]Ziskind-Conhaim L, Mentis GZ, Wiesner EP, Titus DJ: Synaptic integration of rhythmogenic neurons in the locomotor circuitry: the case of Hb9 interneurons. Ann N Y Acad Sci 2010, 1198:72-84.
• [42]Hinckley CA, Hartley R, Wu L, Todd A, Ziskind-Conhaim L: Locomotor-like rhythms in a genetically distinct cluster of interneurons in the mammalian spinal cord. J Neurophysiol 2005, 93:1439-1449.
• [43]Hinckley CA, Wiesner EP, Mentis GZ, Titus DJ, Ziskind-Conhaim L: Sensory modulation of locomotor-like membrane oscillations in Hb9-expressing interneurons. J Neurophysiol 2010, 103:3407-3423.
• [44]Hinckley CA, Ziskind-Conhaim L: Electrical coupling between locomotor-related excitatory interneurons in the mammalian spinal cord. J Neurosci 2006, 26:8477-8483.
• [45]Wilson JM, Cowan AI, Brownstone RM: Heterogeneous electrotonic coupling and synchronization of rhythmic bursting activity in mouse Hb9 interneurons. J Neurophysiol 2007, 98:2370-2381.
• [46]Wilson JM, Hartley R, Maxwell DJ, Todd AJ, Lieberam I, Kaltschmidt JA, Yoshida Y, Jessell TM, Brownstone RM: Conditional rhythmicity of ventral spinal interneurons defined by expression of the Hb9 homeodomain protein. J Neurosci 2005, 25:5710-5719.
• [47]Ziskind-Conhaim L, Wu L, Wiesner EP: Persistent sodium current contributes to induced voltage oscillations in locomotor-related hb9 interneurons in the mouse spinal cord. J Neurophysiol 2008, 100:2254-2264.
• [48]Higashijima S, Masino MA, Mandel G, Fetcho JR: Engrailed-1 expression marks a primitive class of inhibitory spinal interneuron. J Neurosci 2004, 24:5827-5839.
• [49]Tallafuss A, Gibson D, Morcos P, Li Y, Seredick S, Eisen J, Washbourne P: Turning gene function ON and OFF using sense and antisense photo-morpholinos in zebrafish. Development 2012, 139:1691-1699.
• [50]Lewis KE, Eisen JS: Paraxial mesoderm specifies zebrafish primary motoneuron subtype identity. Development 2004, 131:891-902.
• [51]Chen JA, Huang YP, Mazzoni EO, Tan GC, Zavadil J, Wichterle H: Mir-17-3p controls spinal neural progenitor patterning by regulating Olig2/Irx3 cross-repressive loop. Neuron 2011, 69:721-735.
• [52]Dessaud E, Ribes V, Balaskas N, Yang LL, Pierani A, Kicheva A, Novitch BG, Briscoe J, Sasai N: Dynamic assignment and maintenance of positional identity in the ventral neural tube by the morphogen sonic hedgehog. PLoS Biol 2010, 8:e1000382.
• [53]Shin J, Park HC, Topczewska JM, Mawdsley DJ, Appel B: Neural cell fate analysis in zebrafish using olig2 BAC transgenics. Methods Cell Sci 2003, 25:7-14.
• [54]Flanagan-Steet H, Fox MA, Meyer D, Sanes JR: Neuromuscular synapses can form in vivo by incorporation of initially aneural postsynaptic specializations. Development 2005, 132:4471-4481.
• [55]Westerfield M: The Zebrafish Book. A Guide for the Laboratory Use of Zebrafish (Danio rerio). 5th edition. University of Oregon Press, Eugene; 2007.
• [56]Kimmel CB, Ballard WW, Kimmel SR, Ullmann B, Schilling TF: Stages of embryonic development of the zebrafish. Dev Dyn 1995, 203:253-310.
• [57]Kwan KM, Fujimoto E, Grabher C, Mangum BD, Hardy ME, Campbell DS, Parant JM, Yost HJ, Kanki JP, Chien CB: The Tol2kit: a multisite gateway-based construction kit for Tol2 transposon transgenesis constructs. Dev Dyn 2007, 236:3088-3099.
• [58]Kawakami K, Takeda H, Kawakami N, Kobayashi M, Matsuda N, Mishina M: A transposon-mediated gene trap approach identifies developmentally regulated genes in zebrafish. Dev Cell 2004, 7:133-144.
• [59]Cheesman SE, Layden MJ, Von Ohlen T, Doe CQ, Eisen JS: Zebrafish and fly Nkx6 proteins have similar CNS expression patterns and regulate motoneuron formation. Development 2004, 131:5221-5232.
• [60]Thisse C, Thisse B: High-resolution in situ hybridization to whole-mount zebrafish embryos. Nat Protoc 2008, 3:59-69.
• [61]Hale LA, Fowler DK, Eisen JS: Netrin signaling breaks the equivalence between two identified zebrafish motoneurons revealing a new role of intermediate targets. PLoS One 2011, 6:e25841.