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Highlights: [•] Neural crest-derived cells (NCDCs) exist in adult submandibular glands (SMGs). [•] Sox10 may be a reliable marker for NCDCs in adulthood. [•] NCDCs from adult SMGs expressed Gpr4 and Ednrb at higher levels. [•] NCDCs in adult SMGs have characteristic expression in cell surface molecules. [ABSTRACT FROM AUTHOR]

Abstract: An important goal of synthetic biology is to construct reaction circuits with artificial responses by assembling modulated biological elements into living cells. While many such attempts have been based upon the cellular transcriptional apparatus, the use of the post-translational machinery remains relatively rare. Here we report the reconstruction in Escherichia coli of a protein-based artificial module based upon elements of a eukaryotic cell signaling pathway. The module shows a switch-like ultrasensitive response, using the opposing functions of a protein kinase and a phosphatase. The switch is acutely responsive to the kinase:phosphatase ratio, and can be modulated as a function of the expression level of the substrate. We can theoretically predict the response of this module and can control its steepness based on these predictions. Future work will demonstrate the potential of this controllable protein-based switch to be incorporated into artificial circuits. [Copyright &y& Elsevier]

Tyrosyl-tRNA synthetase (TyrRS) catalyzes the tyrosylation of tRNATyr in a two-step reaction. TyrRS has the “HIGH” and “KMSKS” motifs, which play essential roles in the formation of the tyrosyl-adenylate from tyrosine and ATP. Here, we determined the crystal structures of Archaeoglobus fulgidus and Pyrococcus horikoshii TyrRSs in the l-tyrosine-bound form at 1.8Å and 2.2Å resolutions, respectively, and that of Aeropyrum pernix TyrRS in the substrate-free form at 2.2 Å. The conformation of the KMSKS motif differs among the three TyrRSs. In the A.pernix TyrRS, the KMSKS loop conformation corresponds to the ATP-bound “closed” form. In contrast, the KMSKS loop of the P.horikoshii TyrRS forms a novel 310 helix, which appears to correspond to the “semi-closed” form. This conformation enlarges the entrance to the tyrosine-binding pocket, which facilitates the pyrophosphate ion release after the tyrosyl-adenylate formation, and probably is involved in the initial tRNA binding. The KMSSS loop of the A.fulgidus TyrRS is somewhat farther from the active site and is stabilized by hydrogen bonds. Based on the three structures, possible structural changes of the KMSKS motif during the tyrosine activation reaction are discussed. We suggest that the insertion sequence just before the KMSKS motif, which exists in some archaeal species, enhances the binding affinity of the TyrRS for its cognate tRNA. In addition, a non-proline cis peptide bond, which is involved in the tRNA binding, is conserved among the archaeal TyrRSs. [Copyright &y& Elsevier]

Neural crest-derived cells (NCDCs), a class of adult stem cells not restricted to embryonic tissues, are attractive tissue regenerative therapy candidates because of their ease of isolation, self-renewing properties, and multipotency. Although adult NCDCs can undergo osteogenic differentiation in vitro , whether they induce bone formation in vivo remains unclear. Previously, our group reported findings showing high amounts of NCDCs scattered throughout nasal concha tissues of adult mice. In the present study, NCDCs in nasal conchae labeled with enhanced green fluorescent protein (EGFP) were collected from adult P0-Cre/CAG-CAT-EGFP double transgenic mice, then cultured in serum-free medium to increase the number. Subsequently, NCDCs were harvested and suspended in type I atelocollagen gel, then an atelocollagen sponge was used as a scaffold for the cell suspension. Atelocollagen scaffolds with NCDCs were placed on bone defects created in a mouse calvarial bone defect model. Over the ensuing 12 weeks, micro-CT and histological analysis findings showed that mice with scaffolds containing NCDCs had slightly greater bone formation as compared to those with a scaffold alone. Furthermore, Raman spectroscopy revealed spectral properties of bone in mice that received scaffolds with NCDCs similar to those of native calvarial bone. Bone regeneration is important not only for gaining bone mass but also chemical properties. These results are the first to show the validity of biomolecule-free adult nasal concha-derived NCDCs for bone regeneration, including the chemical properties of regenerated bone tissue. • NCDCs in adult mouse nasal conchae accelerated regeneration of calvaria bone defects. • Transplantation with NCDCs induced mineralized bone formation. • Bone formed with NCDCs had similar chemical properties as native calvarial bone. • NCDCs are an ideal cell source candidate for bone regenerative strategies. [ABSTRACT FROM AUTHOR]