Newly characterised 5′ and 3′ regions of CACNA1A gene harbour mutations associated with Familial Hemiplegic Migraine and Episodic Ataxia

Liana Veneziano, Serena Guida, Elide Mantuano, Paola Bernard, Patrizia Tarantino, Loredana Boccone, Fuki M. Hisama, Paola Carrera, Carla Jodice, Marina Frontali

Research output: Contribution to journalArticle

Abstract

The CACNA1A gene codes for the α1A pore-forming subunit of Ca2+ voltage-gated Cav2.1 channels. CACNA1A mutations are responsible for Familial Hemiplegic Migraine (FHM) type 1, Episodic Ataxia (EA) type 2 and Spinocerebellar Ataxia type 6. The structure of the human gene includes, at present, 49 exons; however almost nothing is known about the 5′ regulatory region, and there is now evidence suggesting the presence of additional exons at the 3′ of the gene. The 892 bp fragment upstream of exon 1 and its deletion mutants were characterised for their transcriptional activity by using luciferase as a reporter gene. The 3′ region was analysed by Rapid Amplification of the cDNA 3′ End. Both regions were screened for mutations in a series of FHM and EA patients by SSCP and sequencing. At the 5′ end of the gene a minimal promoter region was identified within the first 497 bp from ATG. By screening a larger fragment for mutations, the 5 bp deletion (g.-757_-753delCTTTC) was identified in a FHM patient. The deletion significantly increased the transcriptional activity, most likely due to the removal of half a turn of the DNA helix, changing the orientation of downstream binding sites for transcriptional factors. At the 3′ end of the gene a new exon 48, followed by a strong poly-A signal, was identified as well as a new splice variant. The 5 bp insertion (g.38429_38430insCTTTT) in this exon was found in an EA patient. The two new regions can open the way for the study of human CACNA1A gene expression regulation and can be sites of mutations associated with FHM or EA phenotypes.

Original languageEnglish
Pages (from-to)31-37
Number of pages7
JournalJournal of the Neurological Sciences
Volume276
Issue number1-2
DOIs
Publication statusPublished - Jan 15 2009

Keywords

  • CACNA1A exon 48
  • CACNA1A human gene promoter
  • Cav2.1 channels
  • Episodic Ataxia type 2
  • Familial Hemiplegic Migraine type 1

ASJC Scopus subject areas

  • Clinical Neurology
  • Neurology

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