Zebrafish Slit2 and Slit3 Act Together to Regulate Retinal Axon Crossing at the Midline
Slit-Robo signaling regulates midline crossing of commissural axons in different systems. In zebrafish, all retinofugal axons cross at the optic chiasm to innervate the contralateral tectum. Here, the mutant for the Robo2 receptor presents severe axon guidance defects, which were not completely repr...
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MDPI AG
2022-09-01
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| Series: | Journal of Developmental Biology |
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| Online Access: | https://www.mdpi.com/2221-3759/10/4/41 |
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| author | Camila Davison Gabriela Bedó Flavio R. Zolessi |
| author_facet | Camila Davison Gabriela Bedó Flavio R. Zolessi |
| author_sort | Camila Davison |
| collection | DOAJ |
| description | Slit-Robo signaling regulates midline crossing of commissural axons in different systems. In zebrafish, all retinofugal axons cross at the optic chiasm to innervate the contralateral tectum. Here, the mutant for the Robo2 receptor presents severe axon guidance defects, which were not completely reproduced in a Slit2 ligand null mutant. Since <i>slit3</i> is also expressed around this area at the stage of axon crossing, we decided to analyze the possibility that it collaborates with Slit2 in this process. We found that the disruption of <i>slit3</i> expression by sgRNA-Cas9 injection caused similar, albeit slightly milder, defects than those of the <i>slit2</i> mutant, while the same treatment in the <i>slit2−/−<sup>mz</sup></i> background caused much more severe defects, comparable to those observed in <i>robo2</i> mutants. Tracking analysis of in vivo time-lapse experiments indicated differential but complementary functions of these secreted factors in the correction of axon turn errors around the optic chiasm. Interestingly, RT-qPCR analysis showed a mild increase in <i>slit2</i> expression in <i>slit3</i>-deficient embryos, but not the opposite. Our observations support the previously proposed “repulsive channel” model for Slit-Robo action at the optic chiasm, with both Slits acting in different manners, most probably relating to their different spatial expression patterns. |
| first_indexed | 2024-03-09T16:16:05Z |
| format | Article |
| id | doaj.art-aa701e3eb7254ce8af11eeab4478ad67 |
| institution | Directory Open Access Journal |
| issn | 2221-3759 |
| language | English |
| last_indexed | 2024-03-09T16:16:05Z |
| publishDate | 2022-09-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Journal of Developmental Biology |
| spelling | doaj.art-aa701e3eb7254ce8af11eeab4478ad672023-11-24T15:48:23ZengMDPI AGJournal of Developmental Biology2221-37592022-09-011044110.3390/jdb10040041Zebrafish Slit2 and Slit3 Act Together to Regulate Retinal Axon Crossing at the MidlineCamila Davison0Gabriela Bedó1Flavio R. Zolessi2Sección Biología Celular, Facultad de Ciencias, Universidad de la República, Montevideo 11400, UruguaySección Genética Evolutiva, Facultad de Ciencias, Universidad de la República, Montevideo 11400, UruguaySección Biología Celular, Facultad de Ciencias, Universidad de la República, Montevideo 11400, UruguaySlit-Robo signaling regulates midline crossing of commissural axons in different systems. In zebrafish, all retinofugal axons cross at the optic chiasm to innervate the contralateral tectum. Here, the mutant for the Robo2 receptor presents severe axon guidance defects, which were not completely reproduced in a Slit2 ligand null mutant. Since <i>slit3</i> is also expressed around this area at the stage of axon crossing, we decided to analyze the possibility that it collaborates with Slit2 in this process. We found that the disruption of <i>slit3</i> expression by sgRNA-Cas9 injection caused similar, albeit slightly milder, defects than those of the <i>slit2</i> mutant, while the same treatment in the <i>slit2−/−<sup>mz</sup></i> background caused much more severe defects, comparable to those observed in <i>robo2</i> mutants. Tracking analysis of in vivo time-lapse experiments indicated differential but complementary functions of these secreted factors in the correction of axon turn errors around the optic chiasm. Interestingly, RT-qPCR analysis showed a mild increase in <i>slit2</i> expression in <i>slit3</i>-deficient embryos, but not the opposite. Our observations support the previously proposed “repulsive channel” model for Slit-Robo action at the optic chiasm, with both Slits acting in different manners, most probably relating to their different spatial expression patterns.https://www.mdpi.com/2221-3759/10/4/41optic chiasmaxon guidanceretinal ganglion cellsoptic nerveoptic tracttectum |
| spellingShingle | Camila Davison Gabriela Bedó Flavio R. Zolessi Zebrafish Slit2 and Slit3 Act Together to Regulate Retinal Axon Crossing at the Midline Journal of Developmental Biology optic chiasm axon guidance retinal ganglion cells optic nerve optic tract tectum |
| title | Zebrafish Slit2 and Slit3 Act Together to Regulate Retinal Axon Crossing at the Midline |
| title_full | Zebrafish Slit2 and Slit3 Act Together to Regulate Retinal Axon Crossing at the Midline |
| title_fullStr | Zebrafish Slit2 and Slit3 Act Together to Regulate Retinal Axon Crossing at the Midline |
| title_full_unstemmed | Zebrafish Slit2 and Slit3 Act Together to Regulate Retinal Axon Crossing at the Midline |
| title_short | Zebrafish Slit2 and Slit3 Act Together to Regulate Retinal Axon Crossing at the Midline |
| title_sort | zebrafish slit2 and slit3 act together to regulate retinal axon crossing at the midline |
| topic | optic chiasm axon guidance retinal ganglion cells optic nerve optic tract tectum |
| url | https://www.mdpi.com/2221-3759/10/4/41 |
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