title: HuB (elavl2) mRNA is restricted to the germ cells by post-transcriptional mechanisms including stabilisation of the message by DAZL.
abstract: The ability of germ cells to carry out a gene regulatory program distinct from the surrounding somatic tissue, and their capacity to specify an entire new organism has made them a focus of many studies that seek to understand how specific regulatory mechanisms, particularly post-transcriptional mechanisms, contribute to cell fate. In zebrafish, germ cells are specified through the inheritance of cytoplasmic determinants, termed the germ plasm, which contains a number of maternal mRNAs and proteins. Investigation of several of these messages has revealed that the restricted localisation of these mRNAs to the germ plasm and subsequent germ cells is due to cis-acting sequence elements present in their 3'UTRs. Here we show that a member of the Hu family of RNA-binding proteins, HuB, is maternally provided in the zebrafish embryo and exhibits germ cell specific expression during embryogenesis. Restriction of HuB mRNA to the germ cells is dependent on a number of sequence elements in its 3'UTR, which act to degrade the mRNA in the soma and stabilise it in the germ cells. In addition, we show that the germ cell specific RNA-binding protein DAZL is able to promote HuB mRNA stability and translation in germ cells, and further demonstrate that these activities require a 30 nucleotide element in the 3'UTR. Our study suggests that DAZL specifically binds the HuB 3'UTR and protects the message from degradation and/or enhances HuB translation, leading to the germ cell specific expression of HuB protein.
authors.affiliation: Discipline of Biochemistry, School of Molecular and Biomedical Science, University of Adelaide, Adelaide, Australia.
authors.forename: Sophie E
authors.initials: SE
authors.lastname: Wiszniak
authors.forename: B Kate
authors.initials: BK
authors.lastname: Dredge
authors.forename: Kirk B
authors.initials: KB
authors.lastname: Jensen
mesh_terms: D020413:3' Untranslated Regions / Q000235:genetics; D000818:Animals; D051959:ELAV Proteins / Q000235:genetics* / Q000378:metabolism; D047108:Embryonic Development / Q000235:genetics; D005260:Female; D018507:Gene Expression Regulation, Developmental; D005854:Germ Cells / Q000166:cytology / Q000378:metabolism*; D008297:Male; D009928:Organ Specificity / Q000235:genetics; D020871:RNA Stability / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000378:metabolism*; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics; D013997:Time Factors; D014158:Transcription, Genetic; D015027:Zebrafish / Q000196:embryology / Q000235:genetics*; D029961:Zebrafish Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: D020413:3' Untranslated Regions; C546118:DAZL protein, zebrafish; D051959:ELAV Proteins; C561873:HuB protein, zebrafish; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D029961:Zebrafish Proteins