Ambra1 knockdown in zebrafish leads to incomplete development due to severe defects in organogenesis

Francesca Benato, Tatjana Skobo, Giorgia Gioacchini, Isabella Moro, Fabiola Ciccosanti, Mauro Piacentini, Gian Maria Fimia, Oliana Carnevali, Luisa Dalla Valle

Research output: Contribution to journalArticlepeer-review


AMBRA1 is a positive regulator of the BEC N1-dependent program of autophagy recently identified in mouse. In this study, we cloned the full-length cDNAs of ambra1a and ambra1b zebrafish paralogous genes. As in mouse, both Ambra1 proteins contain the characteristic WD40 repeat region. The transcripts of both genes are present as maternal RNAs in the eggs and display a gradual decline until 8 hpf, being replaced by zygotic mRNAs from 12 hpf onwards. After 24 hpf, the transcripts are mainly localized in the head, suggesting a possible role in brain development. To check their developmental roles, we adopted morpholino knockdown to block either translation (ATGMOs) or splicing (SPLIC MOs). Treatment with ATGMOs causes severe embryonic malformations, as prelarvae could survive for only 3 and 4 days in ambra1a and b morphants, respectively. Treatment with SPLIC MOs led to developmental defects only at a late stage, indicating the importance of maternally supplied ambra1 transcripts. Analysis of the levels of Lc3-II , an autophagosomespecific marker, in the presence of lysosome inhibitors evidenced a reduction in the rate of autophagosome formation in both MOs-injected embryos at 48 hpf, more pronounced in the case of ambra1a gene. Although some defects, such as body growth delay, curved shape and hemorrhagic pericardial cavity were present in both morphants, the occurrence of specific phenotypes, such as major abnormalities of brain development in ambra1a morphants, suggests the possible acquisition of specific functions by the two paralogous genes that are both required during development and do not compensate each other following knockdown.

Original languageEnglish
Pages (from-to)476-495
Number of pages20
Issue number4
Publication statusPublished - Apr 2013


  • Ambra1
  • Autophagy
  • Development
  • Morpholino
  • Zebrafish

ASJC Scopus subject areas

  • Cell Biology
  • Molecular Biology


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