Characterization of a Weak Allele of Zebrafish cloche Mutant

Abstract

Hematopoiesis is a complicated and dynamic process about which the molecular mechanisms remain poorly understood. Danio rerio (zebrafish) is an excellent vertebrate system for studying hematopoiesis and developmental mechanisms. In the previous study, we isolated and identified a cloche 172 (clo 172) mutant, a novel allele compared to the original cloche (clo) mutant, through using complementation test and initial mapping. Here, according to whole mount in-situ hybridization, we report that the endothelial cells in clo 172 mutant embryos, although initially developed, failed to form the functional vascular system eventually. In addition, further characterization indicates that the clo 172 mutant exhibited weaker defects instead of completely lost in primitive erythroid cells and definitive hematopoietic cells compared with the clo s5 mutant. In contrast, primitive myeloid cells were totally lost in clo 172 mutant. Furthermore, these reappeared definitive myeloid cells were demonstrated to initiate from the remaining hematopoietic stem cells (HSCs) in clo 172 mutant, confirmed by the dramatic decrease of lyc in clo 172 runx1w84x double mutant. Collectively, the clo 172 mutant is a weak allele compared to the clo s5 mutant, therefore providing a model for studying the early development of hematopoietic and vascular system, as well as an opportunity to further understand the function of the cloche gene.

Follow that cell: Leukocyte migration in L‐plastin mutant zebrafish

“…2.1 | Fish heterozygous and homozygous for knockout alleles of lcp1 have similar numbers of neutrophils at 2 days postfertilization L-plastin is one of the first markers of primitive hematopoietic cells in zebrafish and is expressed in myeloid precursors as early as 18 h postfertilization (Bennett et al, 2001;Ma et al, 2011). The role of Lplastin is to bundle F-actin, enhancing the stability of membrane protrusions during cell migration.…”

Follow that cell: leukocyte migration in L-plastin mutant zebrafish

“…L-plastin is one of the first markers of primitive hematopoietic cells in zebrafish and is expressed in myeloid precursors as early as 18 hours post-fertilization (Bennett et al 2001; Ma et al 2011). The role of L-plastin is to bundle F-actin, enhancing the stability of membrane protrusions during cell migration.…”

Transcriptional activity of Npas4l controls endothelial lineage specification and restriction in zebrafish

“…The first cloche m39 mutant allele that has been investigated is a spontaneous chromosomal aberration discovered in a semi-wild population of Indonesian zebrafish (Stainier et al, 1995). In two independent ENU screens, additional cloche alleles were discovered: The strong cloche s5 allele was identified in the San Francisco screen shortly after the discovery of the m39 allele, and the weak cloche 172 allele was later identified in a screen for lyC-deficient fish (Ma et al, 2011). (Stainier et al, 1995).…”