title: Effect of genetic background on the developmental expression of c-fos and c-myc in chicken.
abstract: The developmental expression of the protooncogenes, c-fos and c-myc, in muscle and liver of 14- and 19-day embryos and 1-, 6-, 8- and 28-day-old chicks of Athens Canadian Random Bred (ACRB) Single Comb White Leghorn (SCWL) and Peterson X Arbor Acres commercial broiler (PXAA) was determined. For the three stocks of chicken, significant differences were found in c-fos and c-myc expression. For both muscle and liver, averaged across ages, abundance of c-fos RNA was highest in PXAA and lowest in ACRB with differences significant at the P less than 0.01 level. c-myc RNA levels were significantly higher (P less than 0.01) in PXAA than in ACRB or SCWL liver. Taken over the developmental period, expression of c-fos RNA in muscle increased at different rates between breeds from 14-day embryo levels to peak levels in 6- to 8-day-old chicks and declined in 28-day-old chicks. Levels of c-fos were much lower in liver and showed no consistent differences related to developmental stage. A steady decline in c-myc from 14-day embryo levels to 28-day-old chicks was found in both muscle and liver. This decline in c-myc levels generally parallels the decline in relative growth rates which occurs in all breeds over the developmental period. In liver, the fast growing PXAA had the highest levels of c-myc, c-fos, on the other hand, showed elevated levels in PXAA for both muscle and liver and distinctly different patterns between these two tissues over the developmental period, suggesting tissue-specific involvement in growth.
authors.affiliation: Department of Poultry Science, University of Georgia, Athens 30602.
authors.forename: J W
authors.initials: JW
authors.lastname: Kim
authors.forename: D L
authors.initials: DL
authors.lastname: Fletcher
authors.forename: D R
authors.initials: DR
authors.lastname: Campion
authors.forename: H R
authors.initials: HR
authors.lastname: Gaskins
authors.forename: R G
authors.initials: RG
authors.lastname: Dean
mesh_terms: D000818:Animals; D002642:Chick Embryo; D002645:Chickens / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D005786:Gene Expression Regulation; D016762:Genes, fos; D016259:Genes, myc; D008099:Liver / Q000196:embryology / Q000254:growth & development / Q000378:metabolism*; D024510:Muscle Development; D009132:Muscles / Q000196:embryology / Q000378:metabolism*; D012333:RNA, Messenger / Q000096:biosynthesis; D013045:Species Specificity
chemical_list: D012333:RNA, Messenger