Cloning and characterization of a mouse homologue (mNthl1) of Escherichia coli endonuclease III

J Mol Biol. 1998 Oct 2;282(4):761-74. doi: 10.1006/jmbi.1998.2042.


Endonuclease III (endoIII; nth gene product) of Escherichia coli is known to be a DNA repair enzyme having a relatively broad specificity for damaged pyrimidine bases of DNA. Here, we describe the cloning and characterization of the cDNA and the gene for a mouse homologue (mNthl1/mNth1) of endoIII. The cDNA was cloned from a mouse T-cell cDNA library with a probe prepared by PCR using the library and specific PCR primers synthesized based on the reported information of partial amino acid sequences of bovine NTHL1/NTH1 and of EST Data Bases. The cDNA is 1025 nucleotides long and encodes a protein consisting of 300 amino acids with a predicted molecular mass of 33.6 kDa. The amino acid sequence exhibits significant homologies to those of endoIII and its prokaryotic and eukaryotic homologues. The recombinant mNthl1 with a hexahistidine tag was overexpressed in a nth::cmr nei::Kmr double mutant of E. coli, and purified to apparent homogeneity. The enzyme showed thymine glycol DNA glycosylase, urea DNA glycosylase and AP lyase activities. Northern blot analysis indicated that mNthl1 mRNA is about 1 kb and is expressed ubiquitously. A 15 kb DNA fragment containing the mNthl1 gene was cloned from a mouse genomic library and sequenced. The gene consists of six exons and five introns spanning 6.09 kb. The sequenced 5' flanking region lacks a typical TATA box, but contains a CAAT box and putative binding sites for several transcription factors such as Ets, Sp1, AP-1 and AP-2. The mNthl1 gene was shown to lie immediately adjacent to the tuberous sclerosis 2 (Tsc2) gene in a 5'-to-5' orientation by sequence analysis and was assigned to chromosome 17A3 by in situ hybridization.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Blotting, Southern
  • Carbon-Oxygen Lyases / metabolism
  • Cloning, Molecular
  • DNA Glycosylases
  • DNA-(Apurinic or Apyrimidinic Site) Lyase
  • Deoxyribonuclease (Pyrimidine Dimer)*
  • Deoxyribonuclease IV (Phage T4-Induced)
  • Endodeoxyribonucleases / chemistry
  • Endodeoxyribonucleases / genetics*
  • Endodeoxyribonucleases / isolation & purification
  • Endodeoxyribonucleases / metabolism*
  • Escherichia coli / enzymology*
  • Escherichia coli / genetics
  • Escherichia coli Proteins*
  • Exons / genetics
  • Expressed Sequence Tags
  • Humans
  • Introns / genetics
  • Mice
  • Mice, Inbred BALB C
  • Molecular Sequence Data
  • N-Glycosyl Hydrolases / metabolism
  • Open Reading Frames / genetics
  • Physical Chromosome Mapping
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Recombinant Fusion Proteins / biosynthesis
  • Recombinant Fusion Proteins / chemistry
  • Recombinant Fusion Proteins / isolation & purification
  • Recombinant Fusion Proteins / metabolism
  • Repressor Proteins / genetics
  • Response Elements / genetics
  • Sequence Homology, Amino Acid
  • Thymine / analogs & derivatives
  • Thymine / metabolism
  • Tuberous Sclerosis Complex 2 Protein
  • Tumor Suppressor Proteins
  • Urea / metabolism


  • Escherichia coli Proteins
  • RNA, Messenger
  • Recombinant Fusion Proteins
  • Repressor Proteins
  • TSC2 protein, human
  • Tsc2 protein, mouse
  • Tuberous Sclerosis Complex 2 Protein
  • Tumor Suppressor Proteins
  • thymine glycol
  • Urea
  • Endodeoxyribonucleases
  • Deoxyribonuclease IV (Phage T4-Induced)
  • endonuclease IV, E coli
  • Deoxyribonuclease (Pyrimidine Dimer)
  • NTH protein, E coli
  • NTHL1 protein, human
  • Nth1 protein, mouse
  • DNA Glycosylases
  • N-Glycosyl Hydrolases
  • Carbon-Oxygen Lyases
  • DNA-(Apurinic or Apyrimidinic Site) Lyase
  • Thymine

Associated data

  • GENBANK/AB001575