Dev101618 2592..2601
نویسندگان
چکیده
The well-known regenerative abilities of planarian flatworms are attributed to a population of adult stem cells called neoblasts that proliferate and differentiate to produce all cell types. A characteristic feature of neoblasts is the presence of large cytoplasmic ribonucleoprotein granules named chromatoid bodies, the function of which has remained largely elusive. This study shows that histone mRNAs are a common component of chromatoid bodies. Our experiments also demonstrate that accumulation of histone mRNAs, which is typically restricted to the S phase of eukaryotic cells, is extended during the cell cycle of neoblasts. The planarian PIWI homologs SMEDWI-1 and SMEDWI-3 are required for proper localization of germinal histone H4 (gH4) mRNA to chromatoid bodies. The association between histone mRNA and chromatoid body components extends beyond gH4 mRNA, since transcripts of other core histone genes were also found in these structures. Additionally, piRNAs corresponding to loci of every core histone type have been identified. Altogether, this work provides evidence that links PIWI proteins and chromatoid bodies to histone mRNA regulation in planarianstemcells. Themolecular similarities betweenneoblasts and undifferentiated cells of other organisms raise the possibility that PIWI proteins might also regulate histone mRNAs in stem cells and germ cells of other metazoans.
منابع مشابه
Multiple splicing defects caused by hERG splice site mutation 2592+1G>A associated with long QT syndrome.
Long QT syndrome type 2 (LQT2) is caused by mutations in the human ether-a-go-go-related gene (hERG). Cryptic splice site activation in hERG has recently been identified as a novel pathogenic mechanism of LQT2. In this report, we characterize a hERG splice site mutation, 2592+1G>A, which occurs at the 5' splice site of intron 10. Reverse transcription-PCR analyses using hERG minigenes transfect...
متن کاملAngiotensinogen Promoter B-Haplotype Associated With Cerebral Small Vessel Disease
Helena Schmidt, Yurii S. Aulchenko, Natascha Schweighofer, Reinhold Schmidt, Sasa Frank, Enhances Basal Transcriptional Activity Angiotensinogen Promoter B-Haplotype Associated With Cerebral Small Vessel Disease Print ISSN: 0039-2499. Online ISSN: 1524-4628 Copyright © 2004 American Heart Association, Inc. All rights reserved. is published by the American Heart Association, 7272 Greenville Aven...
متن کاملA polar nature of benzoic acids extrusion from nitroalkyl benzoates: DFT mechanistic study
Using DFT calculations at various theory levels, quantum-chemical simulations of decomposition paths were performed for a series of nitroalkyl benzoates. It was discovered, that these reactions proceed via polar, but one-step mechanism. It turned out that depending on the nature of the substituent in the ester molecule and on medium polarity, the studied reactions may take place via transition ...
متن کاملStudy on Learner Modeling in Adaptive Learning System
In light of the present situation researches on learner model in Adaptive Learning System at home and abroad, analyze the design principles and characteristics of Adaptive Learning System. Based on these, this paper summarizes the main problems of learner model from dimension of attention, representation method and acquisition path. It puts forward a new learner model called Advanced Learner Mo...
متن کامل