Cloning, characterization, and the complete 56.8-kilobase DNA sequence of the human NOTCH4 gene.

The first complete mammalian genomic sequence reported thus far in the Notch gene family, including a putative promoter region and 30 exons of the human NOTCH4 gene spanning 56.8 kb of DNA, were sequenced. The NOTCH4 locus contains a TATA-less promoter with two putative transcription initiation sites (Inr), three RBP-Jkappa sites, and two GATA recognition sites. Two cDNA isoforms, NOTCH4(L) and NOTCH4(S),were identified. Whereas the NOTCH4(S) isoform contains the entire coding sequence, the NOTCH4(L) isoform has two unspliced intronic sequences between exons 11 and 12 and exons 20 and 21 and a misspliced exon 6. Consistent with these results, two alternatively spliced isoforms of transcripts of approximately 9.3 and 6.7 kb were detected by Northern blot analysis. The predicted amino acid sequence of the NOTCH4 protein based on the NOTCH4(S) cDNA sequence contains 2003 amino acids and includes the predominant motifs of the Notch family: 29 epidermal growth factor (EGF)-like repeats, 3 Notch/lin-12 repeats, a transmembrane region, 6 cdc10/Ankyrin repeats, and a PEST domain.