{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,5]],"date-time":"2026-10-05T18:40:30Z","timestamp":1791225630470,"version":"4.1.0"},"reference-count":50,"publisher":"American Association for the Advancement of Science (AAAS)","issue":"5464","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Science"],"published-print":{"date-parts":[[2000,4,14]]},"abstract":"<jats:p>\n                    The contribution of extrinsic and genetic mechanisms in determining areas of the mammalian neocortex has been a contested issue. This study analyzes the roles of the regulatory genes\n                    <jats:italic>Emx2<\/jats:italic>\n                    and\n                    <jats:italic>Pax6<\/jats:italic>\n                    , which are expressed in opposing gradients in the neocortical ventricular zone, in specifying areas. Changes in the patterning of molecular markers and area-specific connections between the cortex and thalamus suggest that arealization of the neocortex is disproportionately altered in\n                    <jats:italic>Emx2<\/jats:italic>\n                    and\n                    <jats:italic>Pax6<\/jats:italic>\n                    mutant mice in opposing manners predicted from their countergradients of expression: rostral areas expand and caudal areas contract in\n                    <jats:italic>Emx2<\/jats:italic>\n                    mutants, whereas the opposite effect is seen in\n                    <jats:italic>Pax6<\/jats:italic>\n                    mutants. These findings suggest that\n                    <jats:italic>Emx2<\/jats:italic>\n                    and\n                    <jats:italic>Pax6<\/jats:italic>\n                    cooperate to regulate arealization of the neocortex and to confer area identity to cortical cells.\n                  <\/jats:p>","DOI":"10.1126\/science.288.5464.344","type":"journal-article","created":{"date-parts":[[2002,7,27]],"date-time":"2002-07-27T05:45:50Z","timestamp":1027748750000},"page":"344-349","source":"Crossref","is-referenced-by-count":482,"title":["Regulation of Area Identity in the Mammalian Neocortex by\n                    <i>Emx2<\/i>\n                    and\n                    <i>Pax6<\/i>"],"prefix":"10.1126","volume":"288","author":[{"given":"Kathie M.","family":"Bishop","sequence":"first","affiliation":[{"name":"Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Guy","family":"Goudreau","sequence":"additional","affiliation":[{"name":"Max-Planck-Institute for Biophysical Chemistry, Department of Molecular Cell Biology, Am Fassberg 11, 37077 Go\u0308ttingen, Germany."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Dennis D. M.","family":"O'Leary","sequence":"additional","affiliation":[{"name":"Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA."}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"221","reference":[{"key":"e_1_3_1_2_2","doi-asserted-by":"crossref","unstructured":"B. B. Stanfield and D. D. M. O'Leary Nature 313 135 (1985);","DOI":"10.1038\/313135a0"},{"key":"e_1_3_1_2_3","doi-asserted-by":"publisher","DOI":"10.1038\/337265a0"},{"key":"e_1_3_1_2_4","unstructured":"; D. D. M. O'Leary and"},{"key":"e_1_3_1_2_5","doi-asserted-by":"publisher","DOI":"10.1523\/JNEUROSCI.09-07-02230.1989"},{"key":"e_1_3_1_2_6","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.88.6.2083"},{"key":"e_1_3_1_2_7","doi-asserted-by":"crossref","unstructured":"; B. L. Schlaggar and D. D. M. O'Leary Science 252 1556 (1991).","DOI":"10.1126\/science.2047863"},{"key":"#cr-split#-e_1_3_1_3_2.1","doi-asserted-by":"crossref","unstructured":"P. Rakic Science 241 170 (1988)","DOI":"10.1126\/science.3291116"},{"key":"#cr-split#-e_1_3_1_3_2.2","doi-asserted-by":"crossref","unstructured":"D. D. M. O'Leary Trends Neurosci. 12 400 (1989).","DOI":"10.1016\/0166-2236(89)90080-5"},{"key":"e_1_3_1_4_2","doi-asserted-by":"crossref","unstructured":"A. Chenn J. E. Braisted S. K. McConnell D. D. M. O'Leary in Molecular and Cellular Approaches to Neural Development W. M. Cowan L. Zipursky T. Jessell Eds. (Oxford Univ. Press New York 1997) pp. 440\u2013473.","DOI":"10.1093\/acprof:oso\/9780195111668.003.0012"},{"key":"e_1_3_1_5_2","doi-asserted-by":"publisher","DOI":"10.1523\/JNEUROSCI.19-14-05967.1999"},{"key":"e_1_3_1_5_3","doi-asserted-by":"publisher","DOI":"10.1093\/cercor\/9.6.601"},{"key":"e_1_3_1_6_2","doi-asserted-by":"publisher","DOI":"10.1126\/science.285.5429.906"},{"key":"e_1_3_1_7_2","doi-asserted-by":"crossref","unstructured":"Y. Nakagawa J. E. Johnson D. D. M. O'Leary J. Neurosci. 19 10877 (1999).","DOI":"10.1523\/JNEUROSCI.19-24-10877.1999"},{"key":"e_1_3_1_8_2","doi-asserted-by":"publisher","DOI":"10.1111\/j.1460-9568.1996.tb01590.x"},{"key":"e_1_3_1_8_3","doi-asserted-by":"publisher","DOI":"10.1016\/S0925-4773(98)00141-5"},{"key":"e_1_3_1_9_2","unstructured":"K. M. Bishop and D. D. M. O'Leary unpublished observations; see Web fig. 1 available at www.sciencemag.org\/feature\/data\/1045964.shl."},{"key":"e_1_3_1_10_2","doi-asserted-by":"publisher","DOI":"10.1242\/dev.113.4.1435"},{"key":"e_1_3_1_10_3","doi-asserted-by":"publisher","DOI":"10.1523\/JNEUROSCI.14-03-01395.1994"},{"key":"e_1_3_1_11_2","doi-asserted-by":"publisher","DOI":"10.1242\/dev.122.12.3893"},{"key":"e_1_3_1_12_2","doi-asserted-by":"publisher","DOI":"10.1038\/354522a0"},{"key":"e_1_3_1_12_3","unstructured":". The Sey mutation is a point mutation in the Pax6 gene resulting in a truncated nonfunctional protein."},{"key":"e_1_3_1_13_2","doi-asserted-by":"publisher","DOI":"10.1006\/mcne.1997.0626"},{"key":"e_1_3_1_13_3","unstructured":". For simplicity we use the terms \u201cmotor \u201d \u201cauditory \u201d \u201csomatosensory \u201d and \u201cvisual areas\u201d as employed by Suzuki et al. to describe the cadherin expression patterns detected by whole-mount in situ hybridization. The cadherin expression domains approximate the locations of these cortical areas but these relations have not been corroborated anatomically physiologically or functionally. However our interpretations are not dependent on these domains of cadherin expression being either restricted to a specific cortical area or delineating the full extent of a specific area. We use the patterns of cadherin expression as markers for position-dependent molecular properties of neocortical cells that differ across the tangential or \u201careal\u201d extent of the neocortex and presumably are part of a repertoire of molecular markers that define the area identity and characteristics of neocortical cells. Expansions and contractions in the sizes of the cadherin expression domains in Emx2 and Pax6 mutants are evidence of changes in the position-dependent molecular properties of neocortical cells."},{"key":"e_1_3_1_14_2","unstructured":"Embryonic day 18.5 (E18.5) embryos were obtained from timed-pregnant matings of Emx2 heterozygous mice maintained on a C57BL\/6J background (E0.5 = noon of day of vaginal plug detection). Animal care was in accordance with institutional guidelines. Littermate sets of cortices from wild type heterozygote and homozygous mutants were analyzed to control for differences in developmental rate. Whole-mount in situ hybridization of cortices {modified from work by D. Henrique et al. [ Nature 375 787 (1995)]} used digoxygenin-labeled riboprobes encoding Cad6 and Cad8. Emx2 mice were genotyped by polymerase chain reaction on tail DNA. Whole-mount in situ hybridizations were quantified with the Image program from the National Institutes of Health. Quantification was done blinded to genotype."},{"key":"e_1_3_1_15_2","unstructured":"Whole-mount in situ hybridization on E18.5 Pax6 mutant brains was performed as in (13). Embryos were obtained from matings of heterozygous Sey mice maintained on a C57BL\/6J \u00d7 DBA\/2J background. Sey mice were genotyped by examination of the eyes: homozygous mutants lack eyes and heterozygotes have reduced external eye size and a pronounced size reduction of the developing lens at E18.5. Analysis was as in (13) done blinded to genotype."},{"key":"e_1_3_1_16_2","unstructured":"Although Sey \/ Sey brains lack thalamic input to the cortex (18) this is not the cause of the observed changes in cortical Cad6 and Cad8 expression patterns. Normal expression of areal markers including cadherins has been observed in the neocortex of Gbx2 and Mash-1 mutant mice which lack thalamocortical input (5 6)."},{"key":"e_1_3_1_17_2","doi-asserted-by":"publisher","DOI":"10.1002\/cne.902280407"},{"key":"e_1_3_1_17_3","doi-asserted-by":"publisher","DOI":"10.1002\/cne.903350103"},{"key":"e_1_3_1_18_2","unstructured":"E18.5 Emx2 embryos were collected as in (13) and axonal projections between the thalamus and cortex were labeled with the lipophilic dyes DiI and DiA as in work by D. Livy and D. Wahlsten [ Hippocampus 7 2 (1997)]. Care was taken to equate crystal size and placement between littermate sets of wild type heterozygote and homozygote mutants. Placement and sizes of injection sites were verified in sections counterstained with bisbenzimide. Quantification was done blinded to genotype."},{"key":"e_1_3_1_19_2","unstructured":"R. Tuttle J. E. Braisted Y. Nakagawa D. D. M. O'Leary unpublished observations on Sey \/ Sey mice; see also work by H. Kawano et al. [ J. Comp. Neurol. 408 147 (1999)] for similar findings on Pax6 mutant rats."},{"key":"e_1_3_1_20_2","unstructured":"K. M. Bishop G. Goudreau D. D. M. O'Leary unpublished observations."},{"key":"e_1_3_1_21_2","doi-asserted-by":"publisher","DOI":"10.1002\/j.1460-2075.1992.tb05319.x"},{"key":"e_1_3_1_22_2","doi-asserted-by":"publisher","DOI":"10.1002\/cne.902750304"},{"key":"e_1_3_1_23_2","unstructured":"E18.5 Emx2 embryos were collected as in (13). AChE histochemistry was as in work by B. L. Schlaggar J. A. De Carlos and D. D. M. O'Leary [ Dev. Brain Res. 75 19 (1993)]. In situ hybridization and counterstaining were as in work by R. Tuttle Y. Nakagawa J. E. Johnson and D. D. M. O'Leary [ Development 126 1903 (1999)]."},{"key":"e_1_3_1_24_2","unstructured":"A delay in overall development of the cortex cannot account for our findings. The mutant patterns of cadherin expression and thalamocortical projections do not resemble patterns observed at earlier stages in wild types. For example the domains of cadherin expression do not exhibit significant proportional expansions or contractions during normal embryonic cortical development (6); axons from VP neurons do not transiently invade the visual area at early stages and the somatosensory area later and vice versa for dLG axons; and the distribution of corticothalamic projection neurons is area specific even at the earliest times that they can be labeled (16). Emx2 and Pax6 mutants also show opposite changes in cadherin expression patterns which cannot be accounted for by a delay in cortical development in both mutants."},{"key":"e_1_3_1_25_2","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.95.9.5329"},{"key":"e_1_3_1_25_3","unstructured":"; D. D. M. O'Leary and"},{"key":"e_1_3_1_25_4","first-page":"55","volume":"9","author":"Wilkinson D. G.","year":"1999","unstructured":"Wilkinson D. G., Curr. Opin. Neurobiol. 9, 55 (1999) .","journal-title":"Curr. Opin. Neurobiol."},{"key":"e_1_3_1_26_2","doi-asserted-by":"publisher","DOI":"10.1016\/S0959-437X(96)80062-1"},{"key":"e_1_3_1_27_2","doi-asserted-by":"publisher","DOI":"10.1126\/science.1683715"},{"key":"e_1_3_1_27_3","doi-asserted-by":"publisher","DOI":"10.1006\/dbio.1996.0117"},{"key":"e_1_3_1_28_2","doi-asserted-by":"publisher","DOI":"10.1093\/cercor\/9.6.524"},{"key":"e_1_3_1_29_2","unstructured":"Independent regulation of Emx2 and Pax6 is suggested by their temporal coexpression and the findings that Emx2 is expressed in the Pax6 mutant and that Pax6 is expressed in the Emx2 mutant in graded patterns in the developing neocortex similar to those in wild-type mice ["},{"key":"e_1_3_1_29_3","doi-asserted-by":"publisher","DOI":"10.1242\/dev.122.11.3453"},{"key":"e_1_3_1_29_4","unstructured":"; K. M. Bishop and D. D. M. O'Leary unpublished observations; see Web fig. 2 available at www.sciencemag.org\/feature\/data\/1045964.shl]. In addition analysis of the extra toes mouse mutant (a null mutation of Gli3 ) shows that the loss of Gli3 expression correlates with a loss of Emx2 expression in the rostral forebrain but does not affect Pax6 expression in the developing neocortex (30)."},{"key":"e_1_3_1_30_2","doi-asserted-by":"publisher","DOI":"10.1242\/dev.121.2.439"},{"key":"e_1_3_1_30_3","doi-asserted-by":"publisher","DOI":"10.1242\/dev.125.12.2315"},{"key":"e_1_3_1_30_4","doi-asserted-by":"publisher","DOI":"10.1016\/S0959-4388(98)80004-4"},{"key":"e_1_3_1_31_2","doi-asserted-by":"publisher","DOI":"10.1242\/dev.126.16.3561"},{"key":"e_1_3_1_32_2","unstructured":"We are grateful to P. Gruss for the gift of Emx2 mice M. Goulding for Sey mice and Pax6 plasmid and Y. Nakagawa for Cad6 Cad8 and Gbx2 plasmids and helpful discussions. This work was supported by NIH grant NS31558 (D.D.M.O'L.) the Natural Sciences and Engineering Research Council of Canada (K.M.B.) and the Max-Planck Society and European Commission grant BI04-CT96-0378 (G.G.)."}],"container-title":["Science"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.science.org\/doi\/pdf\/10.1126\/science.288.5464.344","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2024,1,13]],"date-time":"2024-01-13T05:28:03Z","timestamp":1705123683000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.science.org\/doi\/10.1126\/science.288.5464.344"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2000,4,14]]},"references-count":50,"journal-issue":{"issue":"5464","published-print":{"date-parts":[[2000,4,14]]}},"alternative-id":["10.1126\/science.288.5464.344"],"URL":"https:\/\/doi.org\/10.1126\/science.288.5464.344","relation":{"has-review":[{"id-type":"doi","id":"10.3410\/f.1001095.17160","asserted-by":"object"}]},"ISSN":["0036-8075","1095-9203"],"issn-type":[{"value":"0036-8075","type":"print"},{"value":"1095-9203","type":"electronic"}],"subject":[],"published":{"date-parts":[[2000,4,14]]}}}