Isolation, differential splicing and protein expression of a DNase on the human X chromosome.
A systematic search for genes differentially expressed in human tissues resulted in the isolation of a gene encoding a protein with high homology to DNase I. In addition to the recently described cDNA sequence (Parrish et al., 1995) we have isolated a transcript, alternatively spliced in the 5' noncoding region. The gene is located between the QM and the XAP-2 gene in Xq28 and encodes a 302 amino acid protein with 39% identity to human DNase I. Besides a high homology at the nucleotide and amino acid level, most exon-intron boundaries of DNase I and DNase X are identical, indicating that both genes may have evolved from a common ancestor. The predicted function was verified by expression of a recombinant protein in an inducible bacterial system and detection of DNase activity. In contrast to DNase I a 18 kdal amino terminal fragment of the full length 35 kdal protein exhibited DNase activity.
Coy
J F
JF
Deutsches Krebsforschungszentrum, Abteilung Molekulare Genomanalyse, INF 280, Heidelberg, Germany.
Velhagen
I
I
Himmele
R
R
Delius
H
H
Poustka
A
A
Zentgraf
H
H