Matrix Gla protein (MGP) is a secreted vitamin K-dependent protein (VKD) located in the
extracellular matrix and capable of binding calcium through its -carboxyglutamate residues.
Although identified in 1983, transcriptional and post-transcriptional mechanisms regulating its
expression remain unclear

Bensimon-Brito, A.

Cancela, Leonor

Conceição, N.

Gavaia, Paulo J.

Laizé, Vincent

Maia,  Ana-Teresa

Tiago, Daniel

Sapientia

  FEBS International Workshop “New Developments in RNA Biology"        Ilha de Tavira (by Câmara Municipal de Tavira)  1-4 September 2012 Tavira, Algarve, Portugal     3  WELCOME FROM THE ORGANIZERS  Dear Participants:  It is our pleasure to welcome you to FEBS workshop on RNA Biology. RNA has emerged from the “shadow” of DNA and it has become one of the hottest research areas of molecular biology. The study of RNA biology has implications not only for the control of many diseases but also for the understanding of gene expression, translation, and ultimately evolution. In recent years, ribozymes, miRNA, siRNAs and many other functional noncoding RNA have been discovered and evidences indicate that RNA dictates the expression of genetic information and can control the metabolism. RNA is also very important in development, differentiation, and the onset of diseases. The major objective of the workshop is to promote the dialog between experts concerned with different areas of RNA Biology such as Transcription, Ribosomal RNA/tRNA, RNA structure, RNA degradation and quality control, and small RNAs. The number of participants will certainly promote fruitful exchanges, discussions and will contribute to the advancement of Science in the RNA field.  Welcome!   The organizers, M. Leonor Cancela and Cecília M. Arraiano   LOCAL ORGANIZING COMMITTEE Ricardo B. Leite Vincent Laizé Paulo J. Gavaia Natércia Conceição Rute G. Matos Sandra Viegas Susana Domingues José Andrade   19   Matrix Gla protein expression: a complex process involving the use of alternative promoters, multiple splicing events and microRNAs  Cancela ML1,2, Laizé V2, Conceição N2, Tiago DM2, Maia AT1, Bensimon-Brito A2,3,4, Gavaia PJ2  1Department of Biomedical Sciences and Medicine (DCBM), University of Algarve, Faro, Portugal 2Centre of Marine Sciences (CCMAR/CIMAR-LA), University of Algarve, Faro, Portugal 3PhD Program in Biomedical Sciences, DCBM, University of Algarve, Faro, Portugal 4Present address: CEDOC-IGC, Oeiras, Portugal  Matrix Gla protein (MGP) is a secreted vitamin K-dependent protein (VKD) located in the extracellular matrix and capable of binding calcium through its -carboxyglutamate residues. Although identified in 1983, transcriptional and post-transcriptional mechanisms regulating its expression remain unclear. In human, homozygous null-mutations in MGP gene originate the Keutel syndrome, a rare disease with multiple phenotypes associated to abnormal extracellular matrix deposition and calcification, which can be fatal in young adults. Accordingly, KO mice die 6 to 8 weeks after birth due to extensive calcifications in the vascular system, lungs and cartilages, confirming that MGP is a potent physiologic inhibitor of calcification. In all species but mammals, the MGP gene contains 5 exons and two promoters, with distinct transcripts resulting from alternative splicing. Interestingly, in zebrafish, we have also identified distinct transcript variants combining domains from two adjacent genes, MGP and osteocalcin (OC), another VKD protein considered to be evolutionarily related to MGP. This results in proteins with altered biochemical and functional characteristics and recapitulates what was observed in sturgeon, a fish with ancestral features which contains a hybrid form of MGP and OC. Recently, a new exon was identified in primate MGPs which encodes an additional in-frame protein domain distinct from any other sequence already identified, This results in a longer protein with a predicted increase in its calcium binding capability. Bioinformatic analysis has positioned this exon within a DNAse I hypersensitive region, a hyperacetylated domain and a site of enhancer/insulator interaction, which could be involved in the regulation of this alternative splicing event. Because this form has only been observed in human fetal RNA, it may represent a variant linked to development and /or cell differentiation. Both short and long human MGP variants contain the same 3’UTR region, with putative binding sites for miR-148a, conserved in humans and primates, and miR-155, conserved in vertebrates. Luciferase assays indicate that both microRNAs repress MGP expression and inhibition of miR-148a by a specific microRNA inhibitor significantly induces MGP protein expression in human osteosarcoma MG-63 cells, confirming its regulatory potential. Altogether, our data indicate a complex regulation of the MGP gene, both at transcription and post-transcription levels, with what appears to be primate/human specificities.   Acknowledgments: DMT, NC and ABB were supported by post-doctoral and doctoral fellowships (SFRH/BPD/45034/2008, SFRH/BPD/48206/2008 and SFRH/BD/40573/2007, respectively) from the Portuguese Foundation for Science and Technology (FCT). This work was partially funded by Portuguese Calouste Gulbenkian Foundation through program “Na Fronteira das Ciências da Vida”. ATM is supported by a FP7-PEOPLE-2011-CIG grant. O8 

Matrix Gla protein expression: a complex process involving the use of alternative promoters, multiple splicing events and microRNAs

Universidade do Algarve

 
 
FEBS International 
Workshop 
“New Developments 
in RNA Biology" 
 
 
 
 
 
 
 
Ilha de Tavira (by Câmara Municipal de Tavira) 
 
1-4 September 2012 
Tavira, Algarve, Portugal 
 
 
 
 
3 
 
WELCOME FROM THE ORGANIZERS  
Dear Participants: 
 
It is our pleasure to welcome you to FEBS workshop on RNA Biology. RNA has emerged 
from the “shadow” of DNA and it has become one of the hottest research areas of 
molecular biology. The study of RNA biology has implications not only for the control 
of many diseases but also for the understanding of gene expression, translation, and 
ultimately evolution. In recent years, ribozymes, miRNA, siRNAs and many other 
functional noncoding RNA have been discovered and evidences indicate that RNA 
dictates the expression of genetic information and can control the metabolism. RNA is 
also very important in development, differentiation, and the onset of diseases. The 
major objective of the workshop is to promote the dialog between experts concerned 
with different areas of RNA Biology such as Transcription, Ribosomal RNA/tRNA, RNA 
structure, RNA degradation and quality control, and small RNAs. The number of 
participants will certainly promote fruitful exchanges, discussions and will contribute 
to the advancement of Science in the RNA field.  Welcome!  
 
The organizers, M. Leonor Cancela and Cecília M. Arraiano 
 
 
LOCAL ORGANIZING COMMITTEE 
Ricardo B. Leite 
Vincent Laizé 
Paulo J. Gavaia 
Natércia Conceição 
Rute G. Matos 
Sandra Viegas 
Susana Domingues 
José Andrade 
  
19 
 
 
Matrix Gla protein expression: a complex process involving the 
use of alternative promoters, multiple splicing events and 
microRNAs 
 
Cancela ML1,2, Laizé V2, Conceição N2, Tiago DM2, Maia AT1, Bensimon-Brito A2,3,4, Gavaia PJ2 
 
1Department of Biomedical Sciences and Medicine (DCBM), University of Algarve, Faro, Portugal 
2Centre of Marine Sciences (CCMAR/CIMAR-LA), University of Algarve, Faro, Portugal 
3PhD Program in Biomedical Sciences, DCBM, University of Algarve, Faro, Portugal 
4Present address: CEDOC-IGC, Oeiras, Portugal 
 
Matrix Gla protein (MGP) is a secreted vitamin K-dependent protein (VKD) located in the 
extracellular matrix and capable of binding calcium through its -carboxyglutamate residues. 
Although identified in 1983, transcriptional and post-transcriptional mechanisms regulating its 
expression remain unclear. In human, homozygous null-mutations in MGP gene originate the 
Keutel syndrome, a rare disease with multiple phenotypes associated to abnormal extracellular 
matrix deposition and calcification, which can be fatal in young adults. Accordingly, KO mice die 
6 to 8 weeks after birth due to extensive calcifications in the vascular system, lungs and 
cartilages, confirming that MGP is a potent physiologic inhibitor of calcification. In all species but 
mammals, the MGP gene contains 5 exons and two promoters, with distinct transcripts resulting 
from alternative splicing. Interestingly, in zebrafish, we have also identified distinct transcript 
variants combining domains from two adjacent genes, MGP and osteocalcin (OC), another VKD 
protein considered to be evolutionarily related to MGP. This results in proteins with altered 
biochemical and functional characteristics and recapitulates what was observed in sturgeon, a 
fish with ancestral features which contains a hybrid form of MGP and OC. Recently, a new exon 
was identified in primate MGPs which encodes an additional in-frame protein domain distinct 
from any other sequence already identified, This results in a longer protein with a predicted 
increase in its calcium binding capability. Bioinformatic analysis has positioned this exon within a 
DNAse I hypersensitive region, a hyperacetylated domain and a site of enhancer/insulator 
interaction, which could be involved in the regulation of this alternative splicing event. Because 
this form has only been observed in human fetal RNA, it may represent a variant linked to 
development and /or cell differentiation. Both short and long human MGP variants contain the 
same 3’UTR region, with putative binding sites for miR-148a, conserved in humans and primates, 
and miR-155, conserved in vertebrates. Luciferase assays indicate that both microRNAs repress 
MGP expression and inhibition of miR-148a by a specific microRNA inhibitor significantly induces 
MGP protein expression in human osteosarcoma MG-63 cells, confirming its regulatory 
potential. Altogether, our data indicate a complex regulation of the MGP gene, both at 
transcription and post-transcription levels, with what appears to be primate/human specificities.  
 
Acknowledgments: DMT, NC and ABB were supported by post-doctoral and doctoral fellowships 
(SFRH/BPD/45034/2008, SFRH/BPD/48206/2008 and SFRH/BD/40573/2007, respectively) from the 
Portuguese Foundation for Science and Technology (FCT). This work was partially funded by Portuguese 
Calouste Gulbenkian Foundation through program “Na Fronteira das Ciências da Vida”. ATM is supported by 
a FP7-PEOPLE-2011-CIG grant. 
O8 


https://sapientia.ualg.pt/bitstream/10400.1/4469/1/Matrix%20Gla%20protein%20expression.%20A%20complex%20process%20involving%20the%20use%20of%20alternative%20promoters%2c%20multiple%20splicing%20events%20and%20microRNAs.pdf

Matrix Gla protein expression: a complex process involving the use of alternative promoters, multiple splicing events and microRNAs

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