title: Identification and expression analysis of the zebrafish orthologues of the mammalian MAP1LC3 gene family.
abstract: Autophagy is the principle pathway within cells involved in clearing damaged proteins and organelles. Therefore autophagy is necessary to maintain the turnover balance of peptides and homoeostasis. Autophagy occurs at basal levels under normal conditions but can be upregulated by chemical inducers or stress conditions. The zebrafish (Danio rerio) serves as a versatile tool to understand the functions of genes implicated in autophagy. We report the identification of the zebrafish orthologues of mammalian genes MAP1LC3A (map1lc3a) and MAP1LC3B (map1lc3b) by phylogenetic and conserved synteny analysis and we examine their expression during embryonic development. The zebrafish map1lc3a and map1lc3b genes both show maternally contributed transcripts in early embryogenesis. However, levels of map1lc3a transcript steadily increase until at least 120h post-fertilisation while the levels of map1lc3b show a more variable pattern across developmental time. We have also validated the LC3I ratio/LC3I immunoblot autophagy assay in the presence of chloroquine (a lysosomal proteolysis inhibitor). We found that the LC3II/LC3I ratio is significantly increased in the presence of sodium azide with chloroquine supporting that hypoxia induces autophagy in zebrafish. This was supported by our qPCR assay that showed increased map1lc3a transcript levels in the presence of sodium azide. In contrast, levels of map1lc3b transcripts were reduced in the presence of rapamycin but the decrease in the presence of sodium azide did not reach statistical significance. Our study supports the use of zebrafish for analysing the interplay between hypoxia, development and autophagy.
authors: Discipline of Genetics, Zebrafish Genetics Laboratory, School of Molecular and Biomedical Sciences, The University of Adelaide, SA 5005, Australia. Electronic address: swamynathan.ganesan@adelaide.edu.au.
authors: Swamynathan
authors: S
authors: Ganesan
authors: Discipline of Genetics, Zebrafish Genetics Laboratory, School of Molecular and Biomedical Sciences, The University of Adelaide, SA 5005, Australia. Electronic address: seyyed.moussavinik@adelaide.edu.au.
authors: Seyyed Hani
authors: SH
authors: Moussavi Nik
authors: Discipline of Genetics, Zebrafish Genetics Laboratory, School of Molecular and Biomedical Sciences, The University of Adelaide, SA 5005, Australia. Electronic address: morgan.newman@adelaide.edu.au.
authors: Morgan
authors: M
authors: Newman
authors: Discipline of Genetics, Zebrafish Genetics Laboratory, School of Molecular and Biomedical Sciences, The University of Adelaide, SA 5005, Australia. Electronic address: Michael.lardelli@adelaide.edu.au.
authors: Michael
authors: M
authors: Lardelli
mesh_terms: D000818:Animals; D001343:Autophagy / Q000187:drug effects; D015153:Blotting, Western; D004625:Embryo, Nonmammalian / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D047108:Embryonic Development; D018507:Gene Expression Regulation, Developmental; D007166:Immunosuppressive Agents / Q000494:pharmacology; D017403:In Situ Hybridization; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism*; D010802:Phylogeny; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D020123:Sirolimus / Q000494:pharmacology; D015027:Zebrafish / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D007166:Immunosuppressive Agents; D008869:Microtubule-Associated Proteins; D012333:RNA, Messenger; D029961:Zebrafish Proteins; D020123:Sirolimus
keywords: Alzheimer׳s disease; Autophagy; Chloroquine; Hypoxia; LC3; Rapamycin