A newly discovered human alpha-globin gene.
A previously undefined transcript with significant homology to the pseudo-alpha2 region of the alpha-globin locus on human chromosome 16 was detected as part of an effort to better define the transcriptional profiles of human reticulocytes. Cloning and sequencing of that transcript (GenBank AY698022; named mu-globin) revealed an insert with a 423-nucleotide open reading frame. BLASTP and ClustalW and phylogenetic analyses of the predicted protein demonstrated a high level of homology with the avian alpha-D globin. In addition, the heme- and globin-binding amino acids of mu-globin and avian alpha-D globin are largely conserved. Using quantitative real-time polymerase chain reaction (PCR), mu-globin was detected at a level of approximately 0.1% that measured for alpha-globin in erythroid tissues. Erythroid-specific expression was detected by Northern blot analysis, and maximal expression during the erythroblast terminal differentiation was also detected. Despite this highly regulated pattern of mu-globin gene transcription, mu-globin protein was not detected by mass spectrometry. These results suggest the human genome encodes a previously unrecognized globin member of the avian alpha-D family that is transcribed in a highly regulated pattern in erythroid cells.
Goh
Sung-Ho
SH
Molecular Medicine Branch, National Institute of Diabetes, Digestive and Kidney Disease, National Institutes of Health, Bldg 10/Rm 9B17, 10 Center Dr, Bethesda, MD 20892, USA.
Lee
Y Terry
YT
Bhanu
Natarajan V
NV
Cam
Margaret C
MC
Desper
Richard
R
Martin
Brian M
BM
Moharram
Ramy
R
Gherman
Robert B
RB
Miller
Jeffery L
JL
D002454:Cell Differentiation / Q000235:genetics; D003001:Cloning, Molecular; D017124:Conserved Sequence; D004912:Erythrocytes / Q000737:chemistry; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D005914:Globins / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D010802:Phylogeny; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics*; D012156:Reticulocytes / Q000737:chemistry
D012333:RNA, Messenger; D005914:Globins