Study of a new zebrafish mutant defective in primitive myelopoiesis / 南方医科大学学报

<p><b>OBJECTIVE</b>To perform phenotypic identification and characteristic analysis of a new zebrafish mutant 1276 defective in primitive myelopoiesis.</p><p><b>METHODS</b>The AB strain male zebrafish were mutagenized with N-ethyl N-nitrosourea (ENU) to induce mutations in the spermatogonial cells, and the mutations were transmitted to the offsprings. The F3 embryos were screened by neutral red staining for identifying the mutants defective in primitive myelopoiesis. One of the myeloid mutants 1276 was further studied by cytochemistry and whole mount in stiu hybridization (WISH) with different lineage markers.</p><p><b>RESULTS</b>A total of 2140 mutagenized genomes from the 1296 F2 families were analyzed, and 12 mutants were identified to show abnormal signal by neutral red staining. In the primitive hematopoiesis stage, the mutant 1276 showed the absence of neutral red staining-positive cells in the whole body. The expression of microglia marker apoe was totally lost in the head of the mutant, and the expression of the macrophage marker l-plastin was slightly decreased in the head and remained normal in the ventral dorsal aorta region, but the granulocytes and erythrocytes developed normally. in the definitive hematopoiesis stage, the mutant 1276 still showed abnormal macrophages as found in the primitive hematopoiesis stage, but the granulocytes, erythrocytes and lymphocytes appeared normal.</p><p><b>CONCLUSION</b>The zebrafish mutant 1276 shows abnormalities in the function, development and migration of the macrophages in the primitive hematopoiesis stage, which can not be compensated in the definitive hematopoiesis stage.</p>

Forward genetic screening for zebrafish mutants defective in erythropoiesis / 南方医科大学学报

<p><b>OBJECTIVE</b>To screen and identify zebrafish mutants with erythropoiesis defects by N-ethyl-N-nitrosourea (ENU) mutagenesis and large-scale forward genetic screening using beta e 1 as the marker.</p><p><b>METHODS</b>The chemical mutagen ENU was used to treat healthy wild-type male fish (AB strain, F0). The surviving ENU-treated fish were mated with wild-type female fish to generate F1, and further F2 family was generated by F1 family intercross. The adult F2 fish were intercrossed within each F2 family and the resulting F3 embryos from each crossing were subjected to whole mount in situ hybridization (WISH) with the beta e 1 probe. Mutagenesis was performed by treating the male zebrafish with ENU to induce mutations in pre-meiotic germ cells to generate the founders, which were outcrossed to obtained the F1 fish. The F1 fish from different founders were mated to generate the F2 families. F3 embryos from the sibling cross in the F2 family were examined by whole mount in situ hybridization using beta e 1-globin probe. The putative mutants were then characterized with different hematopoiesis markers.</p><p><b>RESULTS AND CONCLUSION</b>We identified 4 beta e 1-deficient mutants with erythropoiesis defects, including two with specific erythiod lineage defects and two with concurrent lymphopoiesis defects.</p>

Forward genetic screening for zebrafish mutants defective in myelopoiesis / 南方医科大学学报

<p><b>OBJECTIVE</b>To identify zebrafish mutants with myelopoiesis defects by ENU mutagenesis and large-scale forward genetic screening.</p><p><b>METHODS</b>Male zebrafish were mutagenized with N-ethyl N-nitrosourea to induce mutations in the spermatogonial cells to generate the founders, which were outcrossed with AB to raise F1 fish. The F1 fish from different founders were mated to generate the F2 families. The F3 embryos from F2 sibling crosses were screened by Sudan black B staining and neutral red staining.</p><p><b>RESULTS</b>A total of 350 F2 families from F1 sibling crosses were screened, and 1424 F2 crosses were analyzed. Six mutations were identified resulting in abnormal Sudan black B staining and neutral red staining, indicating the involvement of neutrophil deficiency or macrophage abnormalities.</p><p><b>CONCLUSION</b>It is simple and cheap to induce and screen myelopoiesis deficiency in zebrafish by ENU chemical mutagenesis and Sudan black B staining and neutral red staining. These mutants shed light on the identification of the genes important to myelopoiesis in zebrafish.</p>