Characterization of Drosophila hemoglobin. Evidence for hemoglobin-mediated respiration in insects.
In contrast to previous assumptions, the fruit fly Drosophila melanogaster possesses hemoglobin. This respiratory protein forms a monomer of about 17 kDa that is not exported into the hemolymph. Recombinant Drosophila hemoglobin displays a typical hexacoordinated deoxy spectrum and binds oxygen with an affinity of 0.12 torr. Four different hemoglobin transcripts have been identified, which are generated by two distinct promoters of the hemoglobin (glob1) gene but are identical in their coding regions. Putative binding sites for hypoxia-regulated transcription factors have been identified in the gene. Hemoglobin synthesis in Drosophila is mainly associated with the tracheal system and the fat body. This suggests that oxygen supply in insects may be more complex than thought previously and may depend on hemoglobin-mediated oxygen transport and storage in addition to simple diffusion.
Hankeln
Thomas
T
Institute of Molecular Genetics, Biosafety Research and Consulting, University of Mainz, D-55099 Mainz, Germany. hankeln@molgen.biologie.uni-mainz.de
Jaenicke
Viviane
V
Kiger
Laurent
L
Dewilde
Sylvia
S
Ungerechts
Guy
G
Schmidt
Marc
M
Urban
Joachim
J
Marden
Michael C
MC
Moens
Luc
L
Burmester
Thorsten
T
D000818:Animals; D001665:Binding Sites; D015153:Blotting, Western; D003001:Cloning, Molecular; D004058:Diffusion; D004330:Drosophila / Q000235:genetics / Q000378:metabolism*; D006454:Hemoglobins / Q000737:chemistry*; D017403:In Situ Hybridization; D007700:Kinetics; D008024:Ligands; D008957:Models, Genetic; D010100:Oxygen / Q000378:metabolism; D011485:Protein Binding; D012313:RNA / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D012119:Respiration; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D013997:Time Factors; D014157:Transcription Factors
D006454:Hemoglobins; D008024:Ligands; D012333:RNA, Messenger; D011994:Recombinant Proteins; D014157:Transcription Factors; D012313:RNA; D010100:Oxygen