Hypoxia-Inducible Factor α and Hif-prolyl Hydroxylase Characterization and Gene Expression in Short-Time Air-Exposed Mytilus galloprovincialis.
Aquatic organisms experience environmental hypoxia as a result of eutrophication and naturally occurring tidal cycles. Mytilus galloprovincialis, being an anoxic/hypoxic-tolerant bivalve, provides an excellent model to investigate the molecular mechanisms regulating oxygen sensing. Across the animal kingdom, inadequacy in oxygen supply is signalled predominantly by hypoxia-inducible factors (HIF) and Hif-prolyl hydroxylases (PHD). In this study, hif-α 5'-end and partial phd mRNA sequences from M. galloprovincialis were obtained. Phylogenetic and molecular characterization of both HIF-α and PHD putative proteins showed shared key features with the respective orthologues from animals strongly suggesting their crucial involvement in the highly conserved oxygen sensing pathway. Both transcripts displayed a tissue-specific distribution with prominent expression in gills. Quantitative gene expression analysis of hif-α and phd mRNAs from gills of M. galloprovincialis demonstrated that both these key sensors are transcriptionally modulated by oxygen availability during the short-time air exposure and subsequent re-oxygenation treatments proving that they are critical players of oxygen-sensing mechanisms in mussels. Remarkably, hif-α gene expression showed a prompt and transient response suggesting the precocious implication of this transcription factor in the early phase of the adaptive response to hypoxia in Mytilus. HIF-α and PHD proteins were modulated in a time-dependent manner with trends comparable to mRNA expression patterns, thus suggesting a central role of their transcriptional regulation in the hypoxia tolerance strategies in marine bivalves. These results provide molecular information about the effects of oxygen deficiency and identify hypoxia-responsive biomarker genes in mussels applicable in ecotoxicological studies of natural marine areas.
Department of Biological and Environmental Sciences, University of Messina, 98166, Messina, Italy. agiannetto@unime.it.
Alessia
A
Giannetto
Department of Biological and Environmental Sciences, University of Messina, 98166, Messina, Italy.
Maria
M
Maisano
Department of Biological and Environmental Sciences, University of Messina, 98166, Messina, Italy.
Tiziana
T
Cappello
Department of Biological and Environmental Sciences, University of Messina, 98166, Messina, Italy.
Sabrina
S
Oliva
Department of Biological and Environmental Sciences, University of Messina, 98166, Messina, Italy.
Vincenzo
V
Parrino
Department of Biological and Environmental Sciences, University of Messina, 98166, Messina, Italy.
Antonino
A
Natalotto
Department of Biological and Environmental Sciences, University of Messina, 98166, Messina, Italy.
Giuseppe
G
De Marco
Department of Biological and Environmental Sciences, University of Messina, 98166, Messina, Italy.
Chiara
C
Barberi
Department of Biological and Environmental Sciences, University of Messina, 98166, Messina, Italy.
Orazio
O
Romeo
Department of Biological and Environmental Sciences, University of Messina, 98166, Messina, Italy.
Angela
A
Mauceri
Department of Biological and Environmental Sciences, University of Messina, 98166, Messina, Italy.
Salvatore
S
Fasulo
D000595:Amino Acid Sequence; D000818:Animals; D015870:Gene Expression / Q000502:physiology; D051793:Hypoxia-Inducible Factor 1 / Q000235:genetics / Q000378:metabolism*; D064799:Hypoxia-Inducible Factor-Proline Dioxygenases / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D049878:Mytilus / Q000235:genetics / Q000378:metabolism*; D010802:Phylogeny; D016415:Sequence Alignment
D051793:Hypoxia-Inducible Factor 1; D064799:Hypoxia-Inducible Factor-Proline Dioxygenases
Gene expression; Hypoxia-inducible factor; Mytilus galloprovincialis; Oxygen sensing