1. Proteins encoded by human Down syndrome critical region gene 1-like 2 (DSCR1L2) mRNA and by a novel DSCR1L2 mRNA isoform interact with cardiac troponin I (TNNI3)
- Author
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Paolo Carinci, Maria Zannotti, Federica Facchin, Silvia Canaider, Luca Lenzi, Pierluigi Strippoli, Flavia Frabetti, Raffaella Casadei, Pietro D'Addabbo, Lorenza Vitale, Cristiana Griffoni, Canaider S, Facchin F, Griffoni C, Casadei R, Vitale L, Lenzi L, Frabetti F, D'Addabbo P, Carinci P, Zannotti M, and Strippoli P
- Subjects
Adult ,Gene isoform ,DNA, Complementary ,Protein family ,Recombinant Fusion Proteins ,Molecular Sequence Data ,Biology ,TNNI3 ,Open Reading Frames ,Two-hybrid system techniques ,Troponin complex ,Yeasts ,Troponin I ,Genetics ,Humans ,Protein Isoforms ,Amino Acid Sequence ,RNA, Messenger ,Cloning, Molecular ,education ,Adaptor Proteins, Signal Transducing ,education.field_of_study ,Reverse Transcriptase Polymerase Chain Reaction ,Alternative splicing ,Proteins ,General Medicine ,Glutathione ,Molecular biology ,Fusion protein ,Human heart ,DOWN SYNDROME CRITICAL REGION GENE 1 ,Sequence Alignment ,Protein Binding - Abstract
Down syndrome critical region gene 1-like 2 (DSCR1L2) belongs to the human DSCR1-like gene family, which also includes DSCR1 and DSCR1L1. Both DSCR1 and DSCR1L1 proteins interact with calcineurin, a calcium/calmodulin-dependent phosphatase. To date, no interactor has been described for DSCR1L2. The aim of this work was to perform a first functional study of DSCR1L2 using yeast two-hybrid analysis conducted on a human heart cDNA library. Here, we report the interaction between DSCR1L2 and the human cardiac troponin I (TNNI3), the heart-specific inhibitory subunit of the troponin complex, a central component of the contractile apparatus. This interaction was confirmed by both yeast cotransformation and GST (glutathione-sepharose transferase) fusion protein assay. Moreover, a new DSCR1L2 mRNA isoform, generated by alternative splicing, was identified and cloned in different tissues: it lacks two central exons, encoding the most conserved domains among the DSCR1-like protein family. A quantitative relative reverse transcription-polymerase chain reaction (RT-PCR) assay showed that in heart tissue the normalized expression level ratio for DSCR1L2 and DSCR1L2-E2E5 mRNA isoforms is 3.5 : 1, respectively. The yeast cotransformation and GST fusion protein assay demonstrated the interaction between this new DSCR1L2 variant and the human cardiac troponin I and the prominent role of DSCR1L2 exon 2 in determining binding between both DSCR1L2 isoforms and TNNI3. These data indicate an entirely new role for a DSCR1-like family gene, suggesting a possible involvement of DSCR1L2 in cardiac contraction.
- Published
- 2006