Chromosomal localization, structure, single-nucleotide polymorphisms, and expression of the human H-protein gene of the glycine cleavage system (GCSH), a candidate gene for nonketotic hyperglycinemia.
Nonketotic hyperglycinemia (NKH) is an inborn error of metabolism caused by deficiency in the glycine cleavage system (GCS); this system consists of four individual constituents, P-, T-, H-, and L-proteins. Several mutations have been identified in P- and T-protein genes, but not in the H-protein gene (GCSH), despite the presence of case reports of H-protein deficiency. To facilitate the mutational and functional analyses of GCSH, we isolated and characterized a human p1-derived artificial chromosome (PAC) clone encoding GCSH. GCSH spanned 13.5kb and consisted of five exons. Using the PAC clone as a probe, we mapped GCSH to chromosome 16q24 by fluorescence in situ hybridization. The transcription initiation site was determined by the oligonucleotide-cap method, and potential binding sites for several transcriptional factors were found in the 5' upstream region. Direct sequencing analysis revealed five single-nucleotide polymorphisms. The expression profiles of P-, T-, and H-protein mRNAs were studied by dot-blot analysis, using total RNA from various human tissues. GCSH was expressed in all 29 tissues examined, while T-protein mRNA was detected in 27 of the 29 tissues. In contrast, the P-protein gene was expressed in a limited number of tissues, such as liver, kidney, brain, pituitary gland, and thyroid gland, suggesting distinct transcriptional regulation of each GCS constituent.
Kure
S
S
Department of Medical Genetics, Tohoku University School of Medicine, Sendai, Japan. skure@mail.cc.tohoku.ac.jp
Kojima
K
K
Kudo
T
T
Kanno
K
K
Aoki
Y
Y
Suzuki
Y
Y
Shinka
T
T
Sakata
Y
Y
Narisawa
K
K
Matsubara
Y
Y
D000483:Alleles; D000594:Amino Acid Oxidoreductases / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D002874:Chromosome Mapping; D002885:Chromosomes, Human, Pair 16 / Q000235:genetics; D003001:Cloning, Molecular; D005091:Exons; D005998:Glycine / Q000097:blood / Q000378:metabolism*; D006801:Humans; D020158:Hyperglycinemia, Nonketotic / Q000201:enzymology / Q000235:genetics*; D017404:In Situ Hybridization, Fluorescence; D007438:Introns; D008969:Molecular Sequence Data; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism
D012333:RNA, Messenger; D000594:Amino Acid Oxidoreductases; D005998:Glycine