Changes in the polysome content of developing Xenopus laevis embryos☆
[摘要] AmethodforpreparingpolysomesfromallembryonicstagesofXenopuslaevisisdescribed.Intheoocyteonlyabout1–2%ofthetotalribosomesarepresentinpolysomes,theremainderbeingadevelopmentalreserve.Uponconversiontoaneggthepolysomecontentrisesbyupto3-fold,andbyaboutafurther2-foldafterfertilization.Thereisonlyasmallfurtherincreaseduringcleavage,butbythetailbudstage,whenorganogenesisbegins,thereisamorerapidrise.Mostoftheribosomesareincorporatedintopolysomesbystage42,shortlybeforefeedingbegins.Atveryearlystages,thechangesinpolysomecontentseemtomirrorthechangesinproteinsynthesis.Atlaterstagesthepolysomecontentsreportedhereprovidetheonlyavailableguidetochangesintherateofproteinsynthesis.Judgedbypolysomecontent,thestage42tadpoleseemstomakeproteinabout20timesfasterthantheunfertilizedegg,thoughitcontainsveryfewmoreribosomes.TherelationshipbetweenpolysomecontentandthesynthesisofvarioustypesofRNAisdiscussed.
[发布日期] [发布机构]
[效力级别] [学科分类] 生物科学（综合）
[关键词] [时效性]
