title: A gene trap transposon eliminates haematopoietic expression of zebrafish Gfi1aa, but does not interfere with haematopoiesis.
abstract: A transposon-mediated gene trap screen identified the zebrafish line qmc551 that expresses a GFP reporter in primitive erythrocytes and also in haemogenic endothelial cells, which give rise to haematopoietic stem and progenitor cells (HSPCs) that seed sites of larval and adult haematopoiesis. The transposon that mediates this GFP expression is located in intron 1 of the gfi1aa gene, one of three zebrafish paralogs that encode transcriptional repressors homologous to mammalian Gfi1 and Gfi1b proteins. In qmc551 transgenics, GFP expression is under the control of the endogenous gfi1aa promoter, recapitulates early gfi1aa expression and allows live observation of gfi1aa promoter activity. While the transposon integration interferes with the expression of gfi1aa mRNA in haematopoietic cells, homozygous qmc551 fish are viable and fertile, and display normal primitive and definitive haematopoiesis. Retained expression of Gfi1b in primitive erythrocytes and up-regulation of Gfi1ab at the onset of definitive haematopoiesis in homozygous qmc551 carriers, are sufficient to allow normal haematopoiesis. This finding contradicts previously published morpholino data that suggested an essential role for zebrafish Gfi1aa in primitive erythropoiesis.
authors.affiliation: School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK.
authors.forename: Roshana
authors.initials: R
authors.lastname: Thambyrajah
authors.affiliation: School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK.
authors.forename: Deniz
authors.initials: D
authors.lastname: Ucanok
authors.affiliation: School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK.
authors.forename: Maryam
authors.initials: M
authors.lastname: Jalali
authors.affiliation: School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK.
authors.forename: Yasmin
authors.initials: Y
authors.lastname: Hough
authors.affiliation: Department of Infection, Immunity & Cardiovascular Disease, University of Sheffield, Medical School, Beech Hill Road, Sheffield S10 2RX, UK; Bateson Centre, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK.
authors.forename: Robert Neil
authors.initials: RN
authors.lastname: Wilkinson
authors.affiliation: School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK.
authors.forename: Kathryn
authors.initials: K
authors.lastname: McMahon
authors.affiliation: School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK.
authors.forename: Chris
authors.initials: C
authors.lastname: Moore
authors.affiliation: School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK. Electronic address: martin.gering@nottingham.ac.uk.
authors.forename: Martin
authors.initials: M
authors.lastname: Gering
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D001483:Base Sequence; D002454:Cell Differentiation; D050676:Core Binding Factor Alpha 2 Subunit / Q000096:biosynthesis; D004251:DNA Transposable Elements / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000096:biosynthesis* / Q000235:genetics; D004912:Erythrocytes / Q000166:cytology* / Q000378:metabolism; D004920:Erythropoiesis / Q000235:genetics*; D018507:Gene Expression Regulation, Developmental; D049452:Green Fluorescent Proteins / Q000235:genetics; D006412:Hematopoietic Stem Cells / Q000166:cytology*; D011401:Promoter Regions, Genetic / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis; D051880:Receptors, Notch / Q000235:genetics / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics / Q000378:metabolism; D015027:Zebrafish / Q000196:embryology* / Q000235:genetics; D029961:Zebrafish Proteins / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D050676:Core Binding Factor Alpha 2 Subunit; D004251:DNA Transposable Elements; D004268:DNA-Binding Proteins; D012333:RNA, Messenger; D051880:Receptors, Notch; C493726:Runx1 protein, mouse; D042461:Vascular Endothelial Growth Factor A; D029961:Zebrafish Proteins; C492589:gfi1ab protein, zebrafish; C467480:vascular endothelial growth factor A, mouse; D049452:Green Fluorescent Proteins
keywords: Endothelial to haematopoietic transition; Gene trap; Gfi1; Haematopoiesis; Haemogenic endothelium; Zebrafish