Department of Cell Biology
Medical Subject Headings
Amino Acid Sequence; Animals; DNA; Expressed Sequence Tags; Gene Expression Profiling; Gene Library; Molecular Sequence Data; Muscle Proteins; Muscle, Skeletal; Protein Isoforms; Sequence Alignment; Sequence Analysis, DNA; Spiders
BACKGROUND: Tarantula has been used as a model system for studying skeletal muscle structure and function, yet data on the genes expressed in tarantula muscle are lacking.
RESULTS: We constructed a cDNA library from Aphonopelma sp. (Tarantula) skeletal muscle and got 2507 high-quality 5'ESTs (expressed sequence tags) from randomly picked clones. EST analysis showed 305 unigenes, among which 81 had more than 2 ESTs. Twenty abundant unigenes had matches to skeletal muscle-related genes including actin, myosin, tropomyosin, troponin-I, T and C, paramyosin, muscle LIM protein, muscle protein 20, a-actinin and tandem Ig/Fn motifs (found in giant sarcomere-related proteins). Matches to myosin light chain kinase and calponin were also identified. These results support the existence of both actin-linked and myosin-linked regulation in tarantula skeletal muscle. We have predicted full-length as well as partial cDNA sequences both experimentally and computationally for myosin heavy and light chains, actin, tropomyosin, and troponin-I, T and C, and have deduced the putative peptides. A preliminary analysis of the structural and functional properties was also carried out. Sequence similarities suggested multiple isoforms of most myofibrillar proteins, supporting the generality of multiple isoforms known from previous muscle sequence studies. This may be related to a mix of muscle fiber types.
CONCLUSION: The present study serves as a basis for defining the transcriptome of tarantula skeletal muscle, for future in vitro expression of tarantula proteins, and for interpreting structural and functional observations in this model species.
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Citation: BMC Genomics. 2009 Mar 19;10:117. © 2009 Zhu et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Link to article on publisher's site
Additional file 1. dbEST submission. Complete submission to the dbEST database. (Format: TXT Size: 2.2MB)
1471-2164-10-117-s2.xls (185 kB)
Additional file 2. Functional annotation of the 5'ESTs. Functional annotation of the 5'ESTs based on Nr matches, Uniprot (SwissProt and TrEMBL) matches, Nt matches and dbEST matches. (Format: XLS Size: 182KB)
1471-2164-10-117-s3.pdf (56 kB)
Additional file 3. Supplementary figures (sequences). The nucleotide and deduced amino acid sequences of putative full-length major muscle proteins are shown. Stop codons and putative polyadenylation signals are underlined. (Format: PDF Size: 387KB)
1471-2164-10-117-s4.pdf (45 kB)
Additional file 4. Supplementary figures (sequence alignments). The alignments of tarantula myofibrillar proteins with other species. (Format: PDF Size: 131KB)