HBG1 explained

Hemoglobin subunit gamma-1 is a protein that in humans is encoded by the HBG1 gene.^[1]

Function

The gamma globin genes (HBG1 and HBG2) are normally expressed in the fetal liver, spleen and bone marrow. Two gamma chains together with two alpha chains constitute fetal hemoglobin (HbF) which is normally replaced by adult hemoglobin (HbA) in the year following birth. In the non-pathological condition known as hereditary persistence of fetal hemoglobin (HPFH), gamma globin expression is continued into adulthood. Also, in cases of beta-thalassemia and related conditions, gamma chain production may be maintained, possibly as a mechanism to compensate for the mutated beta-globin. The two types of gamma chains differ at residue 136 where glycine is found in the G-gamma product (HBG2) and alanine is found in the A-gamma product (HBG1). The former is predominant at birth. The order of the genes in the beta-globin cluster is: 5' - epsilon – gamma-G – gamma-A – delta – beta - 3'.^[2]

Further reading

• Huisman TH, Kutlar F, Gu LH . Gamma chain abnormalities and gamma-globin gene rearrangements in newborn babies of various populations. . Hemoglobin . 15 . 5 . 349–79 . 1992 . 1802881 . 10.3109/03630269108998857 .
• Gelinas R, Yagi M, Endlich B, etal . Sequences of G gamma, A gamma, and beta genes of the Greek (A gamma) HPFH mutant: evidence for a distal CCAAT box mutation in the A gamma gene. . Prog. Clin. Biol. Res. . 191 . 125–39 . 1985 . 2413469 .
• Giardina B, Messana I, Scatena R, Castagnola M . The multiple functions of hemoglobin. . Crit. Rev. Biochem. Mol. Biol. . 30 . 3 . 165–96 . 1995 . 7555018 . 10.3109/10409239509085142 .
• Anderson NL, Anderson NG . The human plasma proteome: history, character, and diagnostic prospects. . Mol. Cell. Proteomics . 1 . 11 . 845–67 . 2003 . 12488461 . 10.1074/mcp.R200007-MCP200. free .
• Chang JC, Kan YW . beta 0 thalassemia, a nonsense mutation in man . Proc. Natl. Acad. Sci. U.S.A. . 76 . 6 . 2886–9 . 1979 . 88735 . 10.1073/pnas.76.6.2886 . 383714 . 1979PNAS...76.2886C . free .
• Saglio G, Ricco G, Mazza U, etal . Human T gamma globin chain is a variant of A gamma chain (A gamma Sardinia) . Proc. Natl. Acad. Sci. U.S.A. . 76 . 7 . 3420–4 . 1979 . 291015 . 10.1073/pnas.76.7.3420 . 383837 . 1979PNAS...76.3420S . free .
• Poon R, Kan YW, Boyer HW . Sequence of the 3'-noncoding and adjacent coding regions of human gamma-globin mRNA . Nucleic Acids Res. . 5 . 12 . 4625–30 . 1979 . 318163 . 342777 .
• Grifoni V, Kamuzora H, Lehmann H, Charlesworth D . A new Hb variant: Hb F Sardinia gamma75(E19) isoleucine leads to threonine found in a family with Hb G Philadelphia, beta-chain deficiency and a Lepore-like haemoglobin indistinguishable from Hb A2 . Acta Haematol. . 53 . 6 . 347–55 . 1975 . 808940 . 10.1159/000208204 .
• Proudfoot NJ, Brownlee GG . 3' non-coding region sequences in eukaryotic messenger RNA . Nature . 263 . 5574 . 211–4 . 1976 . 822353 . 10.1038/263211a0 . 1976Natur.263..211P . 4211839 .
• Marotta CA, Forget BG, Cohne-Solal M, etal . Human beta-globin messenger RNA. I. Nucleotide sequences derived from complementary RNA . J. Biol. Chem. . 252 . 14 . 5019–31 . 1977 . 10.1016/S0021-9258(17)40154-2 . 873928 . free .
• Frier JA, Perutz MF . Structure of human foetal deoxyhaemoglobin . J. Mol. Biol. . 112 . 1 . 97–112 . 1977 . 881729 . 10.1016/S0022-2836(77)80158-7 .
• Ahern E, Holder W, Ahern V, etal . Haemoglobin F Victoria Jubilee (alpha 2 A gamma 2 80 Asp-Try) . Biochim. Biophys. Acta . 393 . 1 . 188–94 . 1975 . 1138921 . 10.1016/0005-2795(75)90230-5.
• Waye JS, Cai SP, Eng B, etal . Clinical course and molecular characterization of a compound heterozygote for sickle hemoglobin and hemoglobin Kenya . Am. J. Hematol. . 41 . 4 . 289–91 . 1993 . 1283810 . 10.1002/ajh.2830410413 . 35045351 .
• Bailey WJ, Hayasaka K, Skinner CG, etal . Reexamination of the African hominoid trichotomy with additional sequences from the primate beta-globin gene cluster . Mol. Phylogenet. Evol. . 1 . 2 . 97–135 . 1994 . 1342932 . 10.1016/1055-7903(92)90024-B .
• Gottardi E, Losekoot M, Fodde R, etal . Rapid identification by denaturing gradient gel electrophoresis of mutations in the gamma-globin gene promoters in non-deletion type HPFH . Br. J. Haematol. . 80 . 4 . 533–8 . 1992 . 1374633 . 10.1111/j.1365-2141.1992.tb04569.x . 27249036 .
• Berry M, Grosveld F, Dillon N . A single point mutation is the cause of the Greek form of hereditary persistence of fetal haemoglobin . Nature . 358 . 6386 . 499–502 . 1992 . 1379347 . 10.1038/358499a0 . 1992Natur.358..499B . 1765/2476 . 4235661 . free .
• Loudianos G, Moi P, Lavinha J, etal . Normal delta-globin gene sequences in Sardinian nondeletional delta beta-thalassemia . Hemoglobin . 16 . 6 . 503–9 . 1993 . 1487421 . 10.3109/03630269208993118 .
• Fucharoen S, Shimizu K, Fukumaki Y . A novel C-T transition within the distal CCAAT motif of the G gamma-globin gene in the Japanese HPFH: implication of factor binding in elevated fetal globin expression . Nucleic Acids Res. . 18 . 17 . 5245–53 . 1990 . 1698280 . 10.1093/nar/18.17.5245 . 332148 .
• Plaseska D, Kutlar F, Wilson JB, etal . Hb F-Jiangsu, the first gamma chain variant with a valine----methionine substitution: alpha 2A gamma 2 134(H12)Val----Met . Hemoglobin . 14 . 2 . 177–83 . 1991 . 1703137 . 10.3109/03630269009046959 .

Notes and References

1. Higgs DR, Vickers MA, Wilkie AO, Pretorius IM, Jarman AP, Weatherall DJ . A review of the molecular genetics of the human alpha-globin gene cluster . Blood . 73 . 5 . 1081–104 . May 1989 . 2649166 . 10.1182/blood.V73.5.1081.1081. free .
2. Web site: Entrez Gene: HBG1 hemoglobin, gamma A.