Isolation of a Brassica napus L. cDNA encoding a putative high-mobility-group HMG I/Y protein

A cDNA encoding a high-mobility-group protein has been isolated from a micr ospore-specific library of Brassica napus. The 930 bp cDNA contains a 612 b p open reading frame encoding a protein of 203 amino acids residues exhibit ing significant homology to HMG-I/Y protein from Arabidopsis thaliana (62%) . The predicted protein contains four copies of the 'AT-hook' motif which i s involved in binding A/T-rich DNA. Southern blotting indicates that the HM G-I/Y gene is a single-copy gene in B. napus. Transcription of the HMG-I/Y gene was detected in all tissues examined, with the highest expression in p ollen-derived embryos. In situ localization studies of flower organs indica te the transcript to be preferentially located in petals and sepals. Subcel lular localization analysis performed during pollen development showed that the transcript of the HMG-I/Y gene is predominantly associated with polyso mes. (C) 2000 Elsevier Science Ireland Ltd. Ail rights reserved.