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Identification of alternative promoter usage for the matrix Gla protein gene
Author(s) -
Conceição Natércia,
Silva Ana C.,
Fidalgo João,
Belo José A.,
Cancela M. Leonor
Publication year - 2005
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/j.1742-4658.2005.04590.x
Subject(s) - biology , gene , exon , promoter , intron , xenopus , microbiology and biotechnology , genetics , reporter gene , 5' flanking region , transcription (linguistics) , gene expression , linguistics , philosophy
Recent cloning of the Xenopus laevis ( Xl ) matrix Gla protein (MGP) gene indicated the presence of a conserved overall structure for this gene between mammals and amphibians but identified an additional 5′‐exon, not detected in mammals, flanked by a functional, calcium‐sensitive promoter, 3042 bp distant from the ATG initiation codon. DNA sequence analysis identified a second TATA‐like DNA motif located at the 3′ end of intron 1 and adjacent to the ATG‐containing second exon. This putative proximal promoter was found to direct transcription of the luciferase reporter gene in the X. laevis A6 cell line, a result confirmed by subsequent deletion mutant analysis. RT‐PCR analysis of Xl MGP gene expression during early development identified a different temporal expression of the two transcripts, strongly suggesting differential promoter activation under the control of either maternally inherited or developmentally induced regulatory factors. Our results provide further evidence of the usefulness of nonmammalian model systems to elucidate the complex regulation of MGP gene transcription and raise the possibility that a similar mechanism of regulation may also exist in mammals.