Conservation of the nucleotide excision repair pathway: characterization of hydra Xeroderma Pigmentosum group F homolog.

Sue Cotterill,Apurva Barve,Saroj Ghaskadbi,Surendra Ghaskadbi

doi:10.1371/journal.pone.0061062

Sue Cotterill, Apurva Barve + Show 2 more

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https://doi.org/10.1371/journal.pone.0061062

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Abstract

Hydra, one of the earliest metazoans with tissue grade organization and nervous system, is an animal with a remarkable regeneration capacity and shows no signs of organismal aging. We have for the first time identified genes of the nucleotide excision repair (NER) pathway from hydra. Here we report cloning and characterization of hydra homolog of xeroderma pigmentosum group F (XPF) gene that encodes a structure-specific 5′ endonuclease which is a crucial component of NER. In silico analysis shows that hydra XPF amino acid sequence is very similar to its counterparts from other animals, especially vertebrates, and shows all features essential for its function. By in situ hybridization, we show that hydra XPF is expressed prominently in the multipotent stem cell niche in the central region of the body column. Ectoderm of the diploblastic hydra was shown to express higher levels of XPF as compared to the endoderm by semi-quantitative RT-PCR. Semi-quantitative RT-PCR analysis also demonstrated that interstitial cells, a multipotent and rapidly cycling stem cell lineage of hydra, express higher levels of XPF mRNA than other cell types. Our data show that XPF and by extension, the NER pathway is highly conserved during evolution. The prominent expression of an NER gene in interstitial cells may have implications for the lack of senescence in hydra.

Highlights

Hydra, a fresh water hydrozoan, is a well-known example of phylum Cnidaria, the earliest animal phylum with true tissue grade organization and nervous system [1]
The sequences were aligned using MUSCLE program in MEGA5.05 [22] and phylogenetic trees based on Neighbour Joining (NJ) and Maximum Parsimony (MP) methods were constructed in MEGA while Maximum Likelihood (ML) tree was constructed with PhyML [23]
Hydra xeroderma pigmentosum group F (XPF) is Very Similar to its Vertebrate Counterparts and the Predicted Protein Possesses Nuclear Localization Signals (NLS), ERCC4 Domain and Nuclease Motif

Summary

Introduction

A fresh water hydrozoan, is a well-known example of phylum Cnidaria, the earliest animal phylum with true tissue grade organization and nervous system [1]. It is diploblastic with a simple cylindrical body bearing a conical hypostome with tentacles at one end and a flattened, mucus-secreting basal disc at the other [2]. It has a remarkably high capacity of regeneration and a propensity to continuously asexually propagate by budding. Isolation, cloning and partial characterization of XPF, an endonuclease of the NER pathway, from hydra

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