Analyses of Soft Tissue from Tyrannosaurus rex Suggest the Presence of Protein

Harvard University, Cambridge, Massachusetts, United States
Science (Impact Factor: 33.61). 05/2007; 316(5822):277-80. DOI: 10.1126/science.1138709
Source: PubMed


We performed multiple analyses of Tyrannosaurus rex (specimen MOR 1125) fibrous cortical and medullary tissues remaining after demineralization. The results indicate that collagen I, the main organic component of bone, has been preserved in low concentrations in these tissues. The findings were independently confirmed by mass spectrometry. We propose a possible chemical pathway that may contribute to this preservation. The presence of endogenous protein in dinosaur bone may validate hypotheses about evolutionary relationships, rates, and patterns of molecular change and degradation, as well as the chemical stability of molecules over time.

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Available from: Mary H Schweitzer
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    • "The survival of biomolecules in ancient tissues has been of great interest for their potential in recovering phylogenetic information for over 30 years. Since the early 1980s, such protein-derived information was retrieved using immunological approaches, [1] [2] methodology that continues in use even recently, [3] [4] despite notorious issues with false-positive results due to cross-reactivity with likely contaminants (e.g., fungi). [5] The criticism that immunological methods are difficult to apply to fossil samples because the assays are pushed to their limits and are prone to yield false-positive results induced doubt into the authenticity of previous results. "
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    ABSTRACT: We report the use of proteomics techniques to study how the fossil bone proteome changes in complexity over one million years. We include the attempted use of a previously unreported methodology in proteome research, to remove the dominant bone collagens using bacterial collagenase as well as conventional shotgun proteomics methodology following digestion with the protease trypsin. In this study we expand upon a set of 19 bovine sub-fossil specimens ranging over one and a half million years that had previously been shown to possess collagen, using a total of 46 LTQ-Orbitrap liquid chromatography/tandem mass spectrometry (LC/MS/MS) analyses containing 462,186 precursor ion analyses. Although many types of proteins can typically be identified in recent bone, in degraded bone we observe a rapid loss of lower abundance proteins. Abundant serum proteins such as serum albumin and alpha-2-HS-glycoprotein appear to be more easily recovered in ancient bone, both being identified in specimens dating to the Early Pleistocene, the earliest period tested in this study. Proteins belonging to the leucine-rich repeat family such as lumican, biglycan and chondroadherin also survive well, possibly because of their interactions with bone collagen. Of these 'survivor proteins' A2HSG shows a remarkable amount of sequence variation, making it potentially one of the most useful proteins to study for species identification and phylogenetic inference in archaeological and palaeontological bone. © 2014 The Authors. Rapid Communications in Mass Spectrometry published by John Wiley & Sons Ltd.
    Full-text · Article · Mar 2014 · Rapid Communications in Mass Spectrometry
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    • "Such imprints would not have defined nuclei or other internal cell structures . In addition, antibodies for avian collagen I exhibited an affinity for collagen isolated from T. rex fossils, and this collagen was degraded by collagenase (Schweitzer et al., 2007a). Antibodies with an affinity for both avian and reptile proteins also had affinity for B. canadensis (Schweitzer et al., 2009). "
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    ABSTRACT: Soft fibrillar bone tissues were obtained from a supraorbital horn of Triceratops horridus collected at the Hell Creek Formation in Montana, USA. Soft material was present in pre and post-decalcified bone. Horn material yielded numerous small sheets of lamellar bone matrix. This matrix possessed visible microstructures consistent with lamellar bone osteocytes. Some sheets of soft tissue had multiple layers of intact tissues with osteocyte-like structures featuring filipodial-like interconnections and secondary branching. Both oblate and stellate types of osteocyte-like cells were present in sheets of soft tissues and exhibited organelle-like microstructures. SEM analysis yielded osteocyte-like cells featuring filipodial extensions of 18-20μm in length. Filipodial extensions were delicate and showed no evidence of any permineralization or crystallization artifact and therefore were interpreted to be soft. This is the first report of sheets of soft tissues from Triceratops horn bearing layers of osteocytes, and extends the range and type of dinosaur specimens known to contain non-fossilized material in bone matrix.
    Full-text · Article · Feb 2013 · Acta histochemica
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    • "Negative controls of sediments extracted in tandem with dinosaur bone, or buffer blanks, did not produce collagen sequence, and indeed collagen is rarely identified as a contaminant in mass spectrometry analyses. The most parsimonius explanation for all the data presented previously [3] [4] [38] [39] [2] is that collagen is preserved in these ancient tissues. Because we have consistently observed microstructures similar in location and morphology to osteocytes and vessels in demineralized bones from various extinct taxa, deriving from different ages, depositional settings and environments [36] [37] [39], it is also more parsimonious to assume a common source (i.e., endogenous to vertebrate organisms from which they derive) than to invoke identical contaminants in different bones from different environments that consistently produce the same structures; structures that are common in both morphology and immunological response to vertebrate bone components. "
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    ABSTRACT: The discovery of soft, transparent microstructures in dinosaur bone consistent in morphology with osteocytes was controversial. We hypothesize that, if original, these microstructures will have molecular features in common with extant osteocytes. We present immunological and mass spectrometry evidence for preservation of proteins comprising extant osteocytes (Actin, Tubulin, PHEX, Histone H4) in osteocytes recovered from two non-avian dinosaurs. Furthermore, antibodies to DNA show localized binding to these microstructures, which also react positively with DNA intercalating stains propidium iodide (PI) and 4',6'-diamidino-2-phenylindole dihydrochloride (DAPI). Each antibody binds dinosaur cells in patterns similar to extant cells. These data are the first to support preservation of multiple proteins and to present multiple lines of evidence for material consistent with DNA in dinosaurs, supporting the hypothesis that these structures were part of the once living animals. We propose mechanisms for preservation of cells and component molecules, and discuss implications for dinosaurian cellular biology.
    Full-text · Article · Oct 2012 · Bone
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