scholarly journals Evidence that gene G7a in the human major histocompatibility complex encodes valyl-tRNA synthetase

1991 ◽  
Vol 278 (3) ◽  
pp. 809-816 ◽  
Author(s):  
S L Hsieh ◽  
R D Campbell
Keyword(s):  
Major Histocompatibility Complex ◽  
Amino Acid ◽  
Molecular Mass ◽  
Trna Synthetase ◽  
Class I ◽  
Major Histocompatibility ◽  
High Sequence Identity ◽  
Human Major Histocompatibility Complex ◽  
Trna Synthetases ◽  
Histocompatibility Complex

At least 36 genes have now been located in a 680 kb segment of DNA between the class I and class II multigene families within the class III region of the human major histocompatibility complex on chromosome 6p21.3. The complete nucleotide sequence of the 4.3 kb mRNA of one of these genes, G7a (or BAT6), has been determined from cDNA and genomic clones. The single-copy G7a gene encodes a 1265-amino-acid protein of molecular mass 140,457 Da. Comparison of the derived amino acid sequence of the G7a protein with the National Biomedical Research Foundation protein databases revealed 42% identity in a 250-amino-acid overlap with Bacillus stearothermophilus valyl-tRNA synthetase, 38.0% identity in a 993-amino-acid overlap with Escherichia coli valyl-tRNA synthetase (val RS), and 48.3% identity in a 1043-amino-acid overlap with Saccharomyces cerevisiae valyl-tRNA synthetase. The protein sequence of G7a contains two short consensus sequences, His-Ile-Gly-His and Lys-Met-Ser-Lys-Ser, which is the typical signature structure of class I tRNA synthetases and indicative of the presence of the Rossman fold. In addition, the molecular mass of the G7a protein is the same as that of other mammalian valyl-tRNA synthetases. These features and the high sequence identity with yeast valyl-tRNA synthetase strongly support the fact that the G7a gene, located within the major histocompatibility complex, encodes the human valyl-tRNA synthetase.

scholarly journals The G9a gene in the human major histocompatibility complex encodes a novel protein containing ankyrin-like repeats

1993 ◽  
Vol 290 (3) ◽  
pp. 811-818 ◽  
Author(s):  
C M Milner ◽  
R D Campbell
Keyword(s):  
Major Histocompatibility Complex ◽  
Amino Acid ◽  
Fusion Protein ◽  
Protein Interactions ◽  
Terminal Region ◽  
Major Histocompatibility ◽  
Class Iii ◽  
Intracellular Protein ◽  
Human Major Histocompatibility Complex ◽  
Histocompatibility Complex

The class III region of the human major histocompatibility complex spans approx. 1.1 Mbp on the short arm of chromosome 6 and is known to contain at least 36 genes. The complete nucleotide sequence of a 3.4 kb mRNA from one of these genes, G9a (or BAT8), has been determined from cDNA and genomic DNA clones. The single-copy G9a gene encodes a protein product of 1001 amino acids with a predicted molecular mass of 111,518 Da. The C-terminal region (residues 730-999) of the G9a protein has been expressed in Escherichia coli as a fusion protein with the 26 kDa glutathione S-transferase of Schistosoma japonicum (Sj26). The fusion protein has been used to raise antisera which, in Western-blot analysis, cross-react specifically with an intracellular protein of approx. 98 kDa. The function of the G9a protein is unknown. However, comparison of the derived amino acid sequence of G9a with the protein databases has revealed interesting similarities with a number of other proteins. The C-terminal region of G9a is 35% identical with a 149 amino acid segment of the Drosophila trithorax protein. In addition the G9a protein has been shown to contain six contiguous copies of a 33-amino acid repeat. This repeat, originally identified in the Notch protein of Drosophila and known as the cdc10/SW16 or ANK repeat, is also found in a number of other human proteins and may be involved in intracellular protein-protein interactions.

scholarly journals cDNA cloning and characterization of the protein encoded by RD, a gene located in the class III region of the human major histocompatibility complex

1993 ◽  
Vol 294 (2) ◽  
pp. 589-593 ◽  
Author(s):  
J Cheng ◽  
K J Macon ◽  
J E Volanakis
Keyword(s):  
Major Histocompatibility Complex ◽  
Amino Acid ◽  
Tandem Repeats ◽  
Cdna Clones ◽  
Major Histocompatibility ◽  
Class Iii ◽  
Human Major Histocompatibility Complex ◽  
Calculated Molecular Mass ◽  
Mouse Cdna ◽  
Histocompatibility Complex

The RD gene, initially defined in the mouse, has been mapped between the Bf and C4A genes in the human major histocompatibility complex class III region. Using the mouse cDNA as a probe, we isolated and sequenced human RD cDNA clones. The composite nucleotide sequence consisted of 1301 nucleotides, excluding a poly(A) tail at the 3′ end. It contained a single open reading frame encoding a polypeptide of 380 amino acid residues with a calculated molecular mass of 42274 Da. The most striking structural feature of the deduced amino acid sequence is a region consisting entirely of 24 tandem repeats of an Arg-Asp (or Glu) dipeptide. The human RD cDNA was expressed in Escherichia coli as a fusion protein with glutathione S-transferase and used to produce antisera in rabbits. Western blot analysis and immunoprecipitation of lysates of biosynthetically labelled HeLa cells indicated that RD is a 44 kDa nuclear protein.

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