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Cloning and characterization of cDNAs for matrix metalloproteinases of regenerating newt limbs.

ABSTRACT: Matrix metalloproteinases (MMPs) of regenerating urodele limbs have been suggested to play crucial roles in the process of the dedifferentiation of cells in the damaged tissues and the ensuing blastema formation because the activation of MMPs is an early and conspicuous event occurring in the amputated limb. MMP cDNAs were cloned as products of the reverse transcription-PCR from cDNA libraries of newt limbs, and their structures were characterized. Three cDNAs encoding newt MMPs (2D-1, 2D-19, and 2D-24) have been cloned from second day postamputation regenerating limbs, and a cDNA (EB-1) was cloned from early bud-stage regenerating limbs. These cDNAs included the full-length coding regions. The deduced amino acid sequences of 2D-1, 2D-19, 2D-24, and EB-1 had a homology with mammalian MMP9, MMP3/10, MMP3/10, and MMP13, respectively. The basic motif of these newt MMP genes was similar to mammalian counterparts and contained regions encoding a putative signal sequence, a propeptide, an active site with three zinc-binding histidine residues, a calcium-binding domain, a hemopexin region, and three key cysteine residues. However, some unique molecular evolutionary features were also found in the newt MMPs. cDNAs of 2D-19 and 2D-24 contained a specific insertion and deletion, respectively. The insertion of 2D-19 is threonine-rich, similar to the threonine cluster found in the collagenase-like sea urchin hatching enzyme. Northern blot analysis showed that the expression levels of the newt MMPs were dramatically increased after amputation, suggesting that they play an important role(s) in tissue remodeling of the regenerating limb.

SUBMITTER: Miyazaki K

PROVIDER: S-EPMC39111 | biostudies-other | 1996 Jun

REPOSITORIES: biostudies-other

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Cloning and characterization of cDNAs for matrix metalloproteinases of regenerating newt limbs.

Miyazaki K K Uchiyama K K Imokawa Y Y Yoshizato K K

Proceedings of the National Academy of Sciences of the United States of America 19960601 13

Matrix metalloproteinases (MMPs) of regenerating urodele limbs have been suggested to play crucial roles in the process of the dedifferentiation of cells in the damaged tissues and the ensuing blastema formation because the activation of MMPs is an early and conspicuous event occurring in the amputated limb. MMP cDNAs were cloned as products of the reverse transcription-PCR from cDNA libraries of newt limbs, and their structures were characterized. Three cDNAs encoding newt MMPs (2D-1, 2D-19, an ...[more]

PMID: 8692902

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Project description:Snake venom metalloproteinases (SVMPs) are a superfamily of zinc-dependent proteases and participate in a number of important biological, physiological and pathophysiological processes. In this work, we simultaneously amplified nine cDNAs encoding different classes of metalloproteinases from glands of four different snake species (Agkistrodon contortrix laticinctus, Crotalus atrox, Crotalus viridis viridis and Agkistrodon piscivorus leucostoma) by RT-PCR with a pair of primers. Among the encoded metalloproteinases, two enzymes (AclVMP-I and AplVMP-I), three enzymes (CaVMP-II, CvvVMP-II and AplVMP-II) and four enzymes (AclVMP-III, CaVMP-III, CvvVMP-III and AplVMP-III) with the characteristic motif (HEXXHXXGXXH) of metalloproteinase belong to type P-I, P-II and P-III enzymes, respectively. Disintegrin domains of CaVMP-II and CvvVMP-II from two Crotatus snakes contain RGD-motif whereas AplVMP-II from Agkistrodon snake has KGD-motif. Instead of R/KGD-motif within disintegrin domain of SVMP-II enzyme, CaVMP-III, CvvVMP-III and AplVMP-III enzymes contain SECD-motif, while AclVMP-III has DDCD-motif in their corresponding position of disintegrin-like domains. There are 12 Cys amino acids in cysterin-rich domains of each P-III enzyme. Moreover, a disintegrin precursor (AplDis) with RGD-motif also simultaneously amplified from the glands of A.p. leucostoma while amplifying AplVMP-II and AplVMP-III, which indicated that different types of SVMPs and related genes are present in a single species of snake and share a consensus sequence at the 3' and 5' untranslated regions. RT-PCR result also showed that P-III is highly expressed in Crotalus snakes than in Agkistrodon snakes. Aligning the deduced amino acid sequence of these enzymes with other SVMPs from GenBank database indicated that this is the first report on the isolation of cDNAs encoding P-II and P-III enzymes from C.v. viridis and A.p. leucostoma snakes. The availability of these SVMP sequences directly facilitated further studies of structure characterization and diversified function analysis.

Project description:BackgroundStudies on amphibian limb regeneration began in the early 1700's but we still do not completely understand the cellular and molecular events of this unique process. Understanding a complex biological process such as limb regeneration is more complicated than the knowledge of the individual genes or proteins involved. Here we followed a systems biology approach in an effort to construct the networks and pathways of protein interactions involved in formation of the accumulation blastema in regenerating axolotl limbs.ResultsWe used the human orthologs of proteins previously identified by our research team as bait to identify the transcription factor (TF) pathways and networks that regulate blastema formation in amputated axolotl limbs. The five most connected factors, c-Myc, SP1, HNF4A, ESR1 and p53 regulate ~50% of the proteins in our data. Among these, c-Myc and SP1 regulate 36.2% of the proteins. c-Myc was the most highly connected TF (71 targets). Network analysis showed that TGF-?1 and fibronectin (FN) lead to the activation of these TFs. We found that other TFs known to be involved in epigenetic reprogramming, such as Klf4, Oct4, and Lin28 are also connected to c-Myc and SP1.ConclusionsOur study provides a systems biology approach to how different molecular entities inter-connect with each other during the formation of an accumulation blastema in regenerating axolotl limbs. This approach provides an in silico methodology to identify proteins that are not detected by experimental methods such as proteomics but are potentially important to blastema formation. We found that the TFs, c-Myc and SP1 and their target genes could potentially play a central role in limb regeneration. Systems biology has the potential to map out numerous other pathways that are crucial to blastema formation in regeneration-competent limbs, to compare these to the pathways that characterize regeneration-deficient limbs and finally, to identify stem cell markers in regeneration.

Project description:BackgroundFollowing amputation, urodele salamander limbs reprogram somatic cells to form a blastema that self-organizes into the missing limb parts to restore the structure and function of the limb. To help understand the molecular basis of blastema formation, we used quantitative label-free liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS)-based methods to analyze changes in the proteome that occurred 1, 4 and 7 days post amputation (dpa) through the mid-tibia/fibula of axolotl hind limbs.ResultsWe identified 309 unique proteins with significant fold change relative to controls (0 dpa), representing 10 biological process categories: (1) signaling, (2) Ca2+ binding and translocation, (3) transcription, (4) translation, (5) cytoskeleton, (6) extracellular matrix (ECM), (7) metabolism, (8) cell protection, (9) degradation, and (10) cell cycle. In all, 43 proteins exhibited exceptionally high fold changes. Of these, the ecotropic viral integrative factor 5 (EVI5), a cell cycle-related oncoprotein that prevents cells from entering the mitotic phase of the cell cycle prematurely, was of special interest because its fold change was exceptionally high throughout blastema formation.ConclusionOur data were consistent with previous studies indicating the importance of inositol triphosphate and Ca2+ signaling in initiating the ECM and cytoskeletal remodeling characteristic of histolysis and cell dedifferentiation. In addition, the data suggested that blastema formation requires several mechanisms to avoid apoptosis, including reduced metabolism, differential regulation of proapoptotic and antiapoptotic proteins, and initiation of an unfolded protein response (UPR). Since there is virtually no mitosis during blastema formation, we propose that high levels of EVI5 function to arrest dedifferentiated cells somewhere in the G1/S/G2 phases of the cell cycle until they have accumulated under the wound epidermis and enter mitosis in response to neural and epidermal factors. Our findings indicate the general value of quantitative proteomic analysis in understanding the regeneration of complex structures.

Dataset Information

Cloning and characterization of cDNAs for matrix metalloproteinases of regenerating newt limbs.

Publications

Cloning and characterization of cDNAs for matrix metalloproteinases of regenerating newt limbs.

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