Molecular cloning of polybromo, a nuclear protein containing multiple domains including five bromodomains, a truncated HMG-box, and two repeats of a novel domain

Gene. 1996 Oct 10;175(1-2):233-40. doi: 10.1016/0378-1119(96)82845-9.


A number of transcription factors that act as adaptor proteins have been found to contain an 87 amino acid domain called the bromodomain. In a study to identify and characterise bromodomain proteins expressed in chicken cells, a novel gene has been isolated which encodes five repeats of the bromodomain. In addition, the encoded protein, termed polybromo, contains four other domains: an unusual truncated HMG box, two repeats of a novel domain which we term the BAH domain and a sequence related to a region within the regulatory domain of the DNA cytosine-5 methyltransferase enzyme. Polybromo was found to be related to a yeast protein U19102 which has two bromo domains, a BAH domain and the DNA methyltransferase-related sequence. Antibodies that were raised against polybromo were used in confocal microscopy analysis to show that the 180-kDa polybromo protein is located within the nucleus but excluded from the nucleolus. Gel filtration analysis of nuclear extracts demonstrate that polybromo is part of a large complex with a mass of approximately 2 million dalton.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Cells, Cultured
  • Chick Embryo
  • Chickens
  • Cloning, Molecular
  • DNA, Complementary / genetics*
  • DNA-Binding Proteins
  • Methyltransferases / genetics
  • Molecular Sequence Data
  • Nuclear Proteins / genetics*
  • Promoter Regions, Genetic / genetics*
  • Repetitive Sequences, Nucleic Acid
  • Transcription Factors / genetics*


  • DNA, Complementary
  • DNA-Binding Proteins
  • Nuclear Proteins
  • PBRM1 protein, human
  • Transcription Factors
  • Methyltransferases

Associated data

  • GENBANK/U19102
  • GENBANK/X90849