Related Experiment Videos
Identification of a TRAF (TNF receptor-associated factor) gene in Caenorhabditis elegans
H Wajant1, F Mühlenbeck, P Scheurich
1Institute of Cell Biology and Immunology, University of Stuttgart, Allmandring 31, 70569 Stuttgart, Germany.
Abstract:
Many members of the tumor necrosis factor (TNF) receptor superfamily and the interleukin-1 (IL-1) receptor engage intracellular signaling pathways including the nuclear factor kappaB (NF-kappaB)-, c-jun N-terminal kinase (JNK)-, and extracellular signal-regulated kinase (ERK) pathways by direct or indirect interaction with TNF receptor-associated factor (TRAF) molecules. To date, six mammalian members of the TRAF family have been identified. Searching public databases with a sequence pattern comprising 19 conserved amino acid residues derived from the carboxyl-terminal part of the TRAF homology domain, we found significant sequence homologies to a stretch of genomic DNA from Caenorhabditis elegans which encodes 1 of 12 exons of a putative protein. The sequence of this putative protein shows up to 29% sequence identity to the mammalian TRAFs and is therefore designated C. elegans TRAF (CeTRAF). The CeTRAF molecule has an amino-terminal RING finger motif followed by four zinc finger structures and a carboxyl-terminal TRAF domain, a composition which is also found in most of the mammalian TRAFs. Reverse transcription-PCR and sequencing analysis of the respective amplicon clearly demonstrates that CeTRAF is in fact transcribed in C. elegans. The existence of a member of the TRAF family in C. elegans provides strong evidence for evolutionary conserved pathways linking cell surface receptors to activation of JNK, ERK, and NF-kappaB.
Insights
Researchers discovered a new protein in C. elegans, CeTRAF, which is similar to mammalian TNF receptor-associated factors (TRAFs). This finding suggests evolutionarily conserved signaling pathways link cell surface receptors to key cellular responses like NF-kappaB activation.
Area of Science:
- Cell Biology
- Molecular Biology
- Evolutionary Biology
Background:
- Tumor necrosis factor (TNF) receptor superfamily and interleukin-1 (IL-1) receptor signaling involve TNF receptor-associated factors (TRAFs).
- Six mammalian TRAF family members are known, mediating pathways like NF-kappaB, JNK, and ERK.
- TRAFs are crucial adaptors linking cell surface receptors to intracellular signaling cascades.
Purpose of the Study:
- To identify novel TRAF family members in non-mammalian organisms.
- To investigate the evolutionary conservation of TRAF-mediated signaling pathways.
- To characterize a newly identified TRAF homolog in Caenorhabditis elegans.
Main Methods:
- Bioinformatic database searching using conserved TRAF domain sequence patterns.
- Sequence analysis and homology comparison between identified C. elegans protein and mammalian TRAFs.
- Reverse transcription-PCR and sequencing to confirm gene transcription in C. elegans.
Main Results:
- A novel protein, C. elegans TRAF (CeTRAF), was identified in C. elegans with significant sequence homology to mammalian TRAFs.
- CeTRAF shares conserved structural features with mammalian TRAFs, including a RING finger motif and a TRAF domain.
- Reverse transcription-PCR confirmed that CeTRAF is actively transcribed in C. elegans.
Conclusions:
- The discovery of CeTRAF provides strong evidence for the evolutionary conservation of TRAF family proteins.
- This finding supports the existence of conserved signaling pathways from cell surface receptors to NF-kappaB, JNK, and ERK activation across species.
- CeTRAF serves as a model for studying the fundamental mechanisms of TRAF-mediated signaling.