T. Trenkle et al., Major transcript variants of VAV3, a new member of the VAV family of guanine nucleotide exchange factors, GENE, 245(1), 2000, pp. 139-149
VAV3 is a new member of the VAV oncogene family with a strong homology to V
AV and VAV2. A conceptual translation of the cDNA indicates that VAV3 is be
tween 40 and 77% identical to VAV and VAV2 at the amino acid level in all i
dentified functional motifs. This homology suggests that VAV3 occupies a si
milar position in signal transduction as the other family members. A major
variant transcript, VAV3.1, found in both humans and mice, appears to encod
e only the 3' SH3-SH2-SH3 region, which suggests that it may substitute for
the full-length isoform in functions mediated by this domain, or compete w
ith the full-length isoform in functions mediated by more N-terminal motifs
, VAV3.1 either is a partly unspliced mRNA or originates from a different p
romoter. VAV3 transcripts are found in cells of hematopoietic origin, where
VAV is primarily expressed. However, unlike, VAV: the VAV3 and VAV3.1 tran
scripts are also found at varying levels in a wide variety of other tissues
and cell lines. TGF-beta and EGF reversibly down-regulate the abundance of
the VAV3.1 transcript in HaCaT keratinocytes, representing the first obser
vation of transcript regulation of a member of the VAV family by a growth f
actor. (C) 2000 Elsevier Science B.V. All rights reserved.