title: Identification of possible downstream genes required for the extension of peripheral axons in primary sensory neurons.
abstract: The LIM-homeodomain transcription factor Islet2a establishes neuronal identity in the developing nervous system. Our previous study showed that Islet2a function is crucial for extending peripheral axons of sensory neurons in zebrafish embryo. Overexpressing a dominant-negative form of Islet2a significantly reduced peripheral axon extension in zebrafish sensory neurons, implicating Islet2a in the gene regulation required for neurite formation or proper axon growth in developing sensory neurons. Based on this, we conducted systematic screening to isolate genes regulated by Islet2a and affecting the development of axon growth in embryonic zebrafish sensory neurons. The 26 genes selected included some encoding factors involved in neuronal differentiation, axon growth, cellular signaling, and structural integrity of neurons, as well as genes whose functions are not fully determined. We chose four representative candidates as possible Islet2a downstream functional targets (simplet, tppp, tusc5 and tmem59l) and analyzed their respective mRNA expressions in dominant-negative Islet2a-expressing embryos. They are not reported the involvement of axonal extension or their functions in neural cells. Finally, knockdown of these genes suggested their direct actual involvement in the extension of peripheral axons in sensory neurons.
authors: Laboratory for Developmental Gene Regulation, Brain Science Institute, Riken, Japan.
authors: Makoto
authors: M
authors: Aoki
authors: Laboratory for Developmental Gene Regulation, Brain Science Institute, Riken, Japan.
authors: Hiroshi
authors: H
authors: Segawa
authors: Laboratory for Developmental Gene Regulation, Brain Science Institute, Riken, Japan.
authors: Mayumi
authors: M
authors: Naito
authors: Laboratory for Developmental Gene Regulation, Brain Science Institute, Riken, Japan. Electronic address: hitoshi@brain.riken.jp.
authors: Hitoshi
authors: H
authors: Okamoto
mesh_terms: D000818:Animals; D001369:Axons / Q000378:metabolism*; D002478:Cells, Cultured; D018507:Gene Expression Regulation, Developmental; D060850:LIM-Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D011984:Sensory Receptor Cells / Q000166:cytology* / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation; D015027:Zebrafish / Q000196:embryology* / Q000235:genetics* / Q000378:metabolism; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D060850:LIM-Homeodomain Proteins; D014157:Transcription Factors; D029961:Zebrafish Proteins; C490404:isl2a protein, zebrafish
keywords: Axon extension; Gene regulation; Islet2a; Sensory neuron; Zebrafish