Molecular phenotypes in cultured maple syrup urine disease cells. Complete E1α cDNA sequence and mRNA and subunit contents of the human branched chain α-keto acid dehydrogenase complex

C. W. Fisher, J. L. Chuang, T. A. Griffin, K. S. Lau, R. P. Cox, D. T. Chuang

Research output: Contribution to journalArticle

41 Citations (Scopus)

Abstract

The activity of the branched-chain α-keto acid dehydrogenase complex is deficient in patients with the inherited maple syrup urine disease (MSUD). To elucidate the molecular basis of this metabolic disorder, we have isolated three overlapping cDNA clones encoding the E1α subunit of the human enzyme complex. The composite human E1α cDNA consists of 1783 base pairs encoding the entire human E1α subunit of 400 amino acids with calculated M(r) = 45,552. The human E1α and the previously isolated human E2 cDNAs were used as probes in Northern blot analysis with cultured fibroblasts and lymphoblasts from seven unrelated MSUD patients. The results along with those of Western blotting have revealed five distinct molecular phenotypes according to mRNA and protein-subunit contents. These consist of type I, where the levels of E1α mRNA and E1α and E1β subunits are normal in cells, but E1 activity is deficient; Type II, where the E1α mRNA is present in normal quantity, whereas the contents of E1α and E1β subunits are reduced; Type III, where the level of E1α mRNA is markedly reduced with a concomitant loss of E1α and E1β subunits; Type IV, where the contents of both E2 mRNA and E2 subunits are markedly reduced; and Type V, where the E2 mRNA is normally expressed, but the E2 subunit is markedly reduced or completely absent. Type V includes thiamin-responsive (WG-34) and certain classical MSUD cells. These molecular phenotypes have demonstrated the complexity of MSUD and identified the affected gene in different patients for further characterization.

Original languageEnglish (US)
Pages (from-to)3448-3453
Number of pages6
JournalJournal of Biological Chemistry
Volume264
Issue number6
StatePublished - 1989

Fingerprint

3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide)
Maple Syrup Urine Disease
Complementary DNA
Phenotype
Messenger RNA
Thiamine
Protein Subunits
Fibroblasts
Base Pairing
Northern Blotting
Clone Cells
Genes
Western Blotting
Amino Acids
Composite materials
Enzymes

ASJC Scopus subject areas

  • Biochemistry

Cite this

@article{d38087172b7e4909a940094253901f4a,
title = "Molecular phenotypes in cultured maple syrup urine disease cells. Complete E1α cDNA sequence and mRNA and subunit contents of the human branched chain α-keto acid dehydrogenase complex",
abstract = "The activity of the branched-chain α-keto acid dehydrogenase complex is deficient in patients with the inherited maple syrup urine disease (MSUD). To elucidate the molecular basis of this metabolic disorder, we have isolated three overlapping cDNA clones encoding the E1α subunit of the human enzyme complex. The composite human E1α cDNA consists of 1783 base pairs encoding the entire human E1α subunit of 400 amino acids with calculated M(r) = 45,552. The human E1α and the previously isolated human E2 cDNAs were used as probes in Northern blot analysis with cultured fibroblasts and lymphoblasts from seven unrelated MSUD patients. The results along with those of Western blotting have revealed five distinct molecular phenotypes according to mRNA and protein-subunit contents. These consist of type I, where the levels of E1α mRNA and E1α and E1β subunits are normal in cells, but E1 activity is deficient; Type II, where the E1α mRNA is present in normal quantity, whereas the contents of E1α and E1β subunits are reduced; Type III, where the level of E1α mRNA is markedly reduced with a concomitant loss of E1α and E1β subunits; Type IV, where the contents of both E2 mRNA and E2 subunits are markedly reduced; and Type V, where the E2 mRNA is normally expressed, but the E2 subunit is markedly reduced or completely absent. Type V includes thiamin-responsive (WG-34) and certain classical MSUD cells. These molecular phenotypes have demonstrated the complexity of MSUD and identified the affected gene in different patients for further characterization.",
author = "Fisher, {C. W.} and Chuang, {J. L.} and Griffin, {T. A.} and Lau, {K. S.} and Cox, {R. P.} and Chuang, {D. T.}",
year = "1989",
language = "English (US)",
volume = "264",
pages = "3448--3453",
journal = "Journal of Biological Chemistry",
issn = "0021-9258",
publisher = "American Society for Biochemistry and Molecular Biology Inc.",
number = "6",

}

TY - JOUR

T1 - Molecular phenotypes in cultured maple syrup urine disease cells. Complete E1α cDNA sequence and mRNA and subunit contents of the human branched chain α-keto acid dehydrogenase complex

AU - Fisher, C. W.

AU - Chuang, J. L.

AU - Griffin, T. A.

AU - Lau, K. S.

AU - Cox, R. P.

AU - Chuang, D. T.

PY - 1989

Y1 - 1989

N2 - The activity of the branched-chain α-keto acid dehydrogenase complex is deficient in patients with the inherited maple syrup urine disease (MSUD). To elucidate the molecular basis of this metabolic disorder, we have isolated three overlapping cDNA clones encoding the E1α subunit of the human enzyme complex. The composite human E1α cDNA consists of 1783 base pairs encoding the entire human E1α subunit of 400 amino acids with calculated M(r) = 45,552. The human E1α and the previously isolated human E2 cDNAs were used as probes in Northern blot analysis with cultured fibroblasts and lymphoblasts from seven unrelated MSUD patients. The results along with those of Western blotting have revealed five distinct molecular phenotypes according to mRNA and protein-subunit contents. These consist of type I, where the levels of E1α mRNA and E1α and E1β subunits are normal in cells, but E1 activity is deficient; Type II, where the E1α mRNA is present in normal quantity, whereas the contents of E1α and E1β subunits are reduced; Type III, where the level of E1α mRNA is markedly reduced with a concomitant loss of E1α and E1β subunits; Type IV, where the contents of both E2 mRNA and E2 subunits are markedly reduced; and Type V, where the E2 mRNA is normally expressed, but the E2 subunit is markedly reduced or completely absent. Type V includes thiamin-responsive (WG-34) and certain classical MSUD cells. These molecular phenotypes have demonstrated the complexity of MSUD and identified the affected gene in different patients for further characterization.

AB - The activity of the branched-chain α-keto acid dehydrogenase complex is deficient in patients with the inherited maple syrup urine disease (MSUD). To elucidate the molecular basis of this metabolic disorder, we have isolated three overlapping cDNA clones encoding the E1α subunit of the human enzyme complex. The composite human E1α cDNA consists of 1783 base pairs encoding the entire human E1α subunit of 400 amino acids with calculated M(r) = 45,552. The human E1α and the previously isolated human E2 cDNAs were used as probes in Northern blot analysis with cultured fibroblasts and lymphoblasts from seven unrelated MSUD patients. The results along with those of Western blotting have revealed five distinct molecular phenotypes according to mRNA and protein-subunit contents. These consist of type I, where the levels of E1α mRNA and E1α and E1β subunits are normal in cells, but E1 activity is deficient; Type II, where the E1α mRNA is present in normal quantity, whereas the contents of E1α and E1β subunits are reduced; Type III, where the level of E1α mRNA is markedly reduced with a concomitant loss of E1α and E1β subunits; Type IV, where the contents of both E2 mRNA and E2 subunits are markedly reduced; and Type V, where the E2 mRNA is normally expressed, but the E2 subunit is markedly reduced or completely absent. Type V includes thiamin-responsive (WG-34) and certain classical MSUD cells. These molecular phenotypes have demonstrated the complexity of MSUD and identified the affected gene in different patients for further characterization.

UR - http://www.scopus.com/inward/record.url?scp=0024539521&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0024539521&partnerID=8YFLogxK

M3 - Article

C2 - 2914958

AN - SCOPUS:0024539521

VL - 264

SP - 3448

EP - 3453

JO - Journal of Biological Chemistry

JF - Journal of Biological Chemistry

SN - 0021-9258

IS - 6

ER -