The cloning, genomic organization and tissue expression profile of the human DLG5 gene

Abstract

Background: Familial atrial fibrillation, an autosomal dominant disease, was previously mapped to chromosome 10q22. One of the genes mapped to the 10q22 region is DLG5, a member of the MAGUKs (Membrane Associated Gyanylate Kinase) family which mediates intracellular signaling. Only a partial cDNA was available for DLG5. To exclude potential disease inducing mutations, it was necessary to obtain a complete cDNA and genomic sequence of the gene.

Methods: The Northern Blot analysis performed using 3' UTR of this gene indicated the transcript size to be about 7.2 KB. Using race technique and library screening the entire cDNA was cloned. This gene was evaluated by sequencing the coding region and splice functions in normal and affected family members with familial atrial fibrillation. Furthermore, haploid cell lines from affected patients were generated and analyzed for deletions that may have been missed by PCR.

Results: We identified two distinct alternately spliced transcripts of this gene. The genomic sequence of the DLG5 gene spanned 79 KB with 32 exons and was shown to have ubiquitous human tissue expression including placenta, heart, skeletal muscle, liver and pancreas.

Conclusions: The entire cDNA of DLG5 was identified, sequenced and its genomic organization determined.

Figure 1

Six day exposure of Human Multi Tissue Northern Blot (Clontech Cat. #7760-1) probed with EST ym59b11 (with insert size 2.386 Kb which contains exon 31 and exon 32 (3'UTR) of DLG5) shows a transcript of about 7.2 Kb with expression in the heart, absence of expression in brain and abundant expression in placenta.

Figure 2

Genomic organization of the gene DLG5 with 32 exons spliced over 79 Kb region. The protein domains are shown with reference to the exons. Domains not shown here are Regulator of Chromosomal Condensation (RCC1) starting at bp 4333 and the CAAX domain at bp 5536–5545 of the cDNA.