title: Expression of ayu (Plecoglossus altivelis) Pit-1 in Escherichia coli: its purification and immunohistochemical detection using monoclonal antibody.
abstract: The pituitary-specific transcription factor Pit-1 belongs to the family of POU-domain proteins and is known to play an important role in the differentiation of pituitary cells. Here we report the complete nucleotide sequence of cDNA encoding Pit-1 from the brackish water fish, ayu (Plecoglossus altivelis). Nucleotide sequence analysis of 1910 bp of ayu Pit-1 cDNA revealed an open reading frame of 1074 bp that encodes a protein of 358 amino acids containing a POU-specific domain, POU homeodomain, and an STA (Ser/Thr-rich activation) transactivation domain. We inserted the coding region of Pit-1 cDNA, obtained by PCR, into a pET-20b(+) plasmid to produce recombinant Pit-1 in Escherichia coli BL21 (DE3) pLysS cells. Upon induction with isopropyl beta-D-thiogalactopyranoside, Pit-1 was expressed and accumulated as inclusion bodies in E. coli. The protein was then purified in one step by affinity chromatography on a nickel-nitrilotriacetic acid agarose column under denaturing conditions. This method yielded 0.7 mg of highly pure and stable protein per 200 ml of bacterial culture. A band of 40 kDa, resolved as recombinant ayu Pit-1 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, agrees well with the molecular mass calculated from the translated cDNA sequence. The purified recombinant Pit-1 was confirmed in vitro through Western blot analysis, using its monoclonal antibody. This monoclonal antibody detected Pit-1 in the nuclei of ayu developing pituitary by immunohistochemical reaction. It serves as a good reagent for the detection of ayu Pit-1 in situ.
authors.affiliation: Institute of Zoology, Academia Sinica, NanKang, Taipei, Taiwan, Republic of China.
authors.forename: Chi-Chien
authors.initials: CC
authors.lastname: Chiu
authors.forename: Joseph Abraham Christopher
authors.initials: JA
authors.lastname: John
authors.forename: Tzong-Hsiung
authors.initials: TH
authors.lastname: Hseu
authors.forename: Chi-Yao
authors.initials: CY
authors.lastname: Chang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal; D001483:Base Sequence; D015153:Blotting, Western; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D004926:Escherichia coli; D005399:Fishes; D007150:Immunohistochemistry; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D010902:Pituitary Gland / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000302:isolation & purification; D050817:Transcription Factor Pit-1; D014157:Transcription Factors / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism
chemical_list: D000911:Antibodies, Monoclonal; D004268:DNA-Binding Proteins; D011994:Recombinant Proteins; D050817:Transcription Factor Pit-1; D014157:Transcription Factors; C494185:Pou1f1 protein, mouse