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Do the hemoglobinless icefishes have globin genes?

1997; Elsevier BV; Volume: 118; Issue: 4 Linguagem: Inglês

10.1016/s0300-9629(97)00010-8

0300-9629

Ennio Cocca, Manoja Ratnayake-Lecamwasam, Sandra K. Parker, Laura Camardella, Maria Ciaramella, Guido di Prisco, H. William Detrich,

Hemoglobin structure and function

Among piscine taxa, the Antarctic icefishes (family Channichthyidae) prosper in the absence of erythrocytes and hemoglobin, a unique condition among adult vertebrates. The genomes of three icefish species and four red-blooded notothenioid species were probed using α- and β-globin cDNA from the red-blooded Antarctic fish Notothenia coriiceps. High-stringency hybridization signals with the α-globin probe, but none with the β-globin probe, on genomic DNAs of both hemoglobinless and red-blooded fishes suggest that icefishes retain remnants of α-globin genes in their genomes but have lost the gene that encodes for β-globin, either through deletion or through rapid mutation. Northern blot analysis of major hematopoietic and non-hematopoietic tissues shows that the α-globin-related sequences of icefishes are nonexpressed derivatives of the α-globin genes of their red-blooded relatives. Mechanisms leading to the hemoglobinless phenotype are discussed in relation with the expression of myoglobin in the Channichthyidae family.