No evidence for ‘stress’ α-globin genes in chicken

Abstract

Phenylhydrazine-induced anaemia in goats and certain sheep carrying a β^A-globin gene, leads to a switch from adult β^A-globin mRNA to β^C mRNA synthesis¹. The β^C globin chains are also transiently produced late in fetal life. The nucleotide sequence of selected fragments of cloned goat β^C globin gene² corresponds to the amino acid sequence determined some years ago³. A similar reactivation of globin genes has been reported for the baboon, Papio cynocephelus, where anaemic stress also leads to the production of fetal haemoglobin⁴. In the case of anaemic chicken, results of cDNA cloning and nucleotide sequencing experiments suggested that a novel type of α-globin gene, the ‘stress’ gene, is expressed⁵. The existence of such a gene was mainly supported by the fact that the cDNA nucleotide sequence did not agree with any known chicken α-globin chain amino acid sequence. In contrast, we now report results, including a reinvestigation of the α^A-globin amino acid sequence, which reveal that in the anaemic chicken, the α^A gene is expressed, and there is no evidence for a specific stress α-globin gene.