tailieunhanh - Báo cáo khoa học: Identification of alternative promoter usage for the matrix Gla protein gene Evidence for differential expression during early development in Xenopus laevis

Recent cloning of theXenopus 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. | ềFEBS Journal Identification of alternative promoter usage for the matrix Gla protein gene Evidence for differential expression during early development in Xenopus laevis Natércia Conceicao1 Ana C. Silva2 3 Joao Fidalgo1 Jose A. Belo2 3 and M. Leonor Cancela1 1 University of Algarve CCMAR Campus de Gambelas Faro Portugal 2 CBME Campus de Gambelas Faro Portugal 3 Instituto Gulbenkian de Ciencia Oeiras Portugal Keywords alternative promoter development matrix Gla protein Xenopus Correspondence M. L. Cancela University of Algarve-CCMAR Campus de Gambelas 8005-139 Faro Portugal Fax 351 289818353 Tel 351 289800971 E-mail lcancela@ Note These two authors contributed equally to this work. Received 7 December 2004 accepted 1 February 2005 doi 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 XlMGP 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. Matrix Gla protein MGP is a 10 kDa .