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Adenosine deaminase deficiency due to heterozygous abnormality consisting of a deletion of exon 7 and the absence of enzyme mRNA
Author(s) -
Kashii Saburo,
Ito Kazuhiko,
Monden Sumie,
Sasai Yoshiki,
Tsuchida Kunihiro,
Fujita Masahiro,
Kawamoto Hiroshi,
Norioka Mihoko,
Okuma Minoru
Publication year - 1991
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/jcb.240470107
Subject(s) - exon , microbiology and biotechnology , biology , messenger rna , gene , complementary dna , southern blot , adenosine deaminase , point mutation , northern blot , mutation , intron , genetics , enzyme , biochemistry
An adenosine deaminase (ADA;EC 3.5.4.4)‐deficient B lymphoblastoid cell line BADO5 derived from a Japanese patient with severe combined immunodeficiency disease and two B lymphoblastoid cell lines, BAMO5 from his mother and BAFO5 from his father, were characterized. To identify mutations affecting ADA activity, we prepared cDNAs to ADA mRNAs of the BADO5 cell line for nucleotide sequencing. Sequence analysis of one of the BADO5 ADA cDNA clones revealed deletion of exon 7, and one point mutation of base 629 from G to A that did not affect the amino acid sequence. All clones of the BADO5 cell line so far examined showed the absence of exon 7 by Southern blotting analysis. Ribonuclease protection assay with an RNA probe spanning from exon 5 to exon 11 showed that the BADO5 ADA mRNA had a deletion of exon 7, the BAMO5 mRNA had normal length, and the BAFO5 mRNA had two species with a deletion of exon 7 and with normal length. Consequently, the patient's ADA genes resulted from one allele of the BAMO5 ADA gene that did not produce a detectable mRNA, and the other allele of the BAFO5 ADA gene producing an aberrant mRNA without exon 7.