Germinal HPRT splice donor site mutation results in multiple RNA splicing products in T-lymphocyte cultures.
We have used peripheral blood T-lymphocyte cultures to analyze the hprt mutation in two Lesch-Nyhan syndrome males who are cousins and to confirm the carrier status of female members of the family. Both cDNA and genomic DNA sequencing studies show that this patient carries a hitherto undescribed single base deletion in the exon 5 donor splice site sequence (I5: +1, delta G, base number 31635). The largest cDNA product contained all nine hprt exons plus an insertion of 66 bases of intron 5, consistent with the use of a cryptic splice site in intron 5 (aag67/gtaagc). This splicing error would result in a chain terminating codon immediately after exon 5 (I5:2-4, taa) and predicts a polypeptide of 133 amino acids. This loss of the normal splice donor site also results in multiple hprt mRNA species, combining the use of the cryptic splice site in intron 5 and splicing errors involving exons 2-6. In addition to defining a new Lesch-Nyhan mutation (hprtHenryville), these results provide insight into aberrant splicing of hprt mRNA in T-lymphocytes.
Hunter
T C
TC
University of Vermont Genetics Laboratory, Burlington, Vermont 05401, USA.
Melancon
S B
SB
Dallaire
L
L
Taft
S
S
Skopek
T R
TR
Albertini
R J
RJ
O'Neill
J P
JP
D001483:Base Sequence; D002478:Cells, Cultured; D002648:Child; D004247:DNA / Q000235:genetics; D004252:DNA Mutational Analysis; D018076:DNA, Complementary / Q000235:genetics; D005091:Exons / Q000235:genetics; D005260:Female; D006580:Genetic Carrier Screening; D006801:Humans; D007041:Hypoxanthine Phosphoribosyltransferase / Q000235:genetics*; D007223:Infant; D007926:Lesch-Nyhan Syndrome / Q000235:genetics*; D008297:Male; D008969:Molecular Sequence Data; D012326:RNA Splicing / Q000235:genetics*; D017384:Sequence Deletion / Q000235:genetics*; D013601:T-Lymphocytes
D018076:DNA, Complementary; D004247:DNA; D007041:Hypoxanthine Phosphoribosyltransferase