{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,3]],"date-time":"2026-10-03T11:23:22Z","timestamp":1791026602243,"version":"4.1.0"},"reference-count":46,"publisher":"The Company of Biologists","issue":"19","license":[{"start":{"date-parts":[[1997,10,1]],"date-time":"1997-10-01T00:00:00Z","timestamp":875664000000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/www.biologists.com\/user-licence-1-1\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[1997,10,1]]},"abstract":"<jats:title>ABSTRACT<\/jats:title>\n               <jats:p>After fertilization in C. elegans, activities encoded by the maternally expressed par genes appear to establish cellular and embryonic polarity. Loss-of-function mutations in the par genes disrupt anterior-posterior (a-p) asymmetries in early embryos and result in highly abnormal patterns of cell fate. Little is known about how the early asymmetry defects are related to the cell fate patterning defects in par mutant embryos, or about how the par gene products affect the localization and activities of developmental regulators known to specify the cell fate patterns made by individual blastomeres. Examples of such regulators of blastomere identity include the maternal proteins MEX-3 and GLP-1, expressed at high levels anteriorly, and SKN-1 and PAL-1, expressed at high levels posteriorly in early embryos. To better define par gene functions, we examined the expression patterns of MEX-3, PAL-1 and SKN-1, and we analyzed mex-3, pal-1, skn-1 and glp-1 activities in par mutant embryos. We have found that mutational inactivation of each par gene results in a unique phenotype, but in no case do we observe a complete loss of a-p asymmetry. We conclude that no one par gene is required for all a-p asymmetry and we suggest that, in some cases, the par genes act independently of each other to control cell fate patterning and polarity. Finally, we discuss the implications of our findings for understanding how the initial establishment of polarity in the zygote by the par gene products leads to the proper localization of more specifically acting regulators of blastomere identity.<\/jats:p>","DOI":"10.1242\/dev.124.19.3815","type":"journal-article","created":{"date-parts":[[2021,4,23]],"date-time":"2021-04-23T19:20:47Z","timestamp":1619205647000},"page":"3815-3826","source":"Crossref","is-referenced-by-count":62,"title":["The maternal <i>par<\/i> genes and the segregation of cell fate specification activities in early <i>Caenorhabditis elegans<\/i> embryos"],"prefix":"10.1242","volume":"124","author":[{"given":"Bruce","family":"Bowerman","sequence":"first","affiliation":[{"name":"1 Institute of Molecular Biology, University of Oregon, 1370 Franklin Blvd, Eugene, Oregon 97403, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Malene K.","family":"Ingram","sequence":"additional","affiliation":[{"name":"1 Institute of Molecular Biology, University of Oregon, 1370 Franklin Blvd, Eugene, Oregon 97403, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Craig P.","family":"Hunter","sequence":"additional","affiliation":[{"name":"2 Department of Molecular and Cellular Biology, Harvard University, 16 Divinity Avenue, Cambridge, MA 02138, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"237","published-online":{"date-parts":[[1997,10,1]]},"reference":[{"key":"2025021405025132300_DEVELOP_124_19_3815C1","doi-asserted-by":"publisher","first-page":"565","DOI":"10.1016\/0092-8674(89)90437-6","article-title":"Transcript analysis of glp-1 and lin-12, homologous genes required for cell interactions during development of C. elegans","volume":"58","author":"Austin","year":"1989","journal-title":"Cell"},{"key":"2025021405025132300_DEVELOP_124_19_3815C2","doi-asserted-by":"publisher","first-page":"473","DOI":"10.1016\/0896-6273(89)90206-7","article-title":"Pharyngeal pumping continues after laser killing of the pharyngeal nervous system of C. elegans","volume":"3","author":"Avery","year":"1989","journal-title":"Neuron"},{"key":"2025021405025132300_DEVELOP_124_19_3815C3","doi-asserted-by":"publisher","first-page":"621","DOI":"10.1126\/science.7939715","article-title":"Incorporation of homeodomain and bZIP elements into a DNA binding domain by C. elegans SKN-1 protein","volume":"266","author":"Blackwell","year":"1994","journal-title":"Science"},{"key":"2025021405025132300_DEVELOP_124_19_3815C4","doi-asserted-by":"publisher","first-page":"443","DOI":"10.1016\/0092-8674(93)80046-H","article-title":"The maternal gene skn-1 encodes a protein that is distributed unequally in early C. elegans embryos","volume":"74","author":"Bowerman","year":"1993","journal-title":"Cell"},{"key":"2025021405025132300_DEVELOP_124_19_3815C5","doi-asserted-by":"publisher","first-page":"1061","DOI":"10.1016\/0092-8674(92)90078-Q","article-title":"skn-1, a maternally expressed gene required to specify the fate of ventral blastomeres in the early C. elegans embryo","volume":"68","author":"Bowerman","year":"1992","journal-title":"Cell"},{"key":"2025021405025132300_DEVELOP_124_19_3815C6","doi-asserted-by":"publisher","first-page":"3075","DOI":"10.1242\/dev.122.10.3075","article-title":"PAR-2 is asymmetrically distributed and promotes association of P granules and PAR-1 with the cortex in C. elegans embryos","volume":"122","author":"Boyd","year":"1996","journal-title":"Development"},{"key":"2025021405025132300_DEVELOP_124_19_3815C7","doi-asserted-by":"publisher","first-page":"71","DOI":"10.1093\/genetics\/77.1.71","article-title":"The genetics of Caenorhabditis elegans","volume":"77","author":"Brenner","year":"1974","journal-title":"Genetics"},{"key":"2025021405025132300_DEVELOP_124_19_3815C8","doi-asserted-by":"publisher","first-page":"549","DOI":"10.1093\/genetics\/139.2.549","article-title":"Control of cleavage spindle orientation in Caenorhabditis elegans: the role of the genes par-2 and par-3","volume":"139","author":"Cheng","year":"1995","journal-title":"Genetics"},{"key":"2025021405025132300_DEVELOP_124_19_3815C9","doi-asserted-by":"publisher","first-page":"36","DOI":"10.1006\/dbio.1996.8413","article-title":"Genes required for GLP-1 asymmetry in the early C. elegans embryo","volume":"181","author":"Crittenden","year":"1996","journal-title":"Dev. 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