Identification of VAV2 on 9q34 and its exclusion as the tuberous sclerosis gene TSC1

Journal Article · Thu Sep 01 04:00:00 EDT 1994 · American Journal of Human Genetics

OSTI ID:134701

Kwiatkowski, D; Short, M P ^[1]; Jozwiak, S ^[2]

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1. Harvard Medical School, Boston, MA (United States)
2. Children`s Health Center, Warsaw (Poland); and others

One causative gene for tuberous sclerosis, tuberin (TSC2), on chr 16p13 has been identified. A second locus, TSC1, on 9q34 remains unidentified. By exon trapping, we have identified a novel homologue of the VAV oncongene on 9q34 in the critical region for TSC1, which we denote VAV2. The VAV2 mRNA has length 3.0 kb, encodes a protein of 841 to 875 amino acids (alternative splicing), and is widely expressed. The smaller VAV2 protein has 53% identity and 72% similarity to VAV. The VAV2 locus extends from D9S66 (3{prime} end) over 100 kb toward the telomere (5{prime} end). We have excluded VAV2 as TSC1 by the following studies: (1) We have screened 89 TS patients (10 from families showing linkage to chr 9q34, the remainder sporadics) by Southern blot analysis using 3 different restriction enzymes. A PstI polymorphism in the 5{prime} end of the gene (3 alleles, het. 45%) and a TaqI polymorphism in the 3{prime} end of the gene (2 alleles, het. 45%; ? = D9S10) and one rare variant were observed. However, novel fragments not seen in unaffected parents were not seen. (2) Using lymphoblastoid RNA, we performed RT-PCR using nested primers to amplify the entire VAV2 gene in four overlapping reactions of length 700-800 bp. Amplified cDNA was directly cycle-sequenced (CS) using Vent exo polymerase (NEB). In analysis of 14 TS patients RNA we identified four uncommon neutral polymorphisms and a single common polymorphism at base 1785 (Met-Val). All 9 genomic heterozygotes for this latter polymorphism expressed both alleles of VAV2 mRNA by RT-PCR analysis. 6 of these 9 were analyzed by RT-PCR-CS throughout the entire coding region of VAV2. No sequence variations or evidence for deletion were seen.

• OSTI ID: 134701
• Report Number(s): CONF-941009--
• Journal Information: American Journal of Human Genetics, Journal Name: American Journal of Human Genetics Journal Issue: Suppl.3 Vol. 55; ISSN AJHGAG; ISSN 0002-9297
• Country of Publication: United States
• Language: English

Related Subjects

55 BIOLOGY AND MEDICINE
BASIC STUDIES
AMINO ACIDS
BIOLOGICAL MARKERS
DNA SEQUENCING
EXONS
GENETIC MAPPING
HEREDITARY DISEASES
HUMAN CHROMOSOME 16
HUMAN CHROMOSOME 9
MESSENGER-RNA
ONCOGENES
PATIENTS
POLYMERASE CHAIN REACTION
PROTEINS
STATISTICS