Isoform-specific expression of BAG-1 in mouse development

Mech Dev. 2000 Mar 1;91(1-2):355-9. doi: 10.1016/s0925-4773(99)00284-1.


BAG-1 is a family of proteins with diverse activities that range in cultured cells from protection against programmed cell death through to regulation of steroid hormone action. At least three proteins (BAG-1L, BAG-1M and BAG-1) are encoded by the Bag-1 mRNA through the use of alternative translation-initiation sites. To assess the in vivo function of these factors, we have used in situ hybridization and immunohistochemical techniques to determine the distribution of Bag-1 transcript and proteins during mouse development. Bag-1 mRNA was identified in several organs with cartilaginous tissues showing the highest expression levels. The level of expression at some of these sites was downregulated during the course of development. In the immunohistochemical studies, antibodies directed against the BAG-1 proteins stained all the sites identified in the in situ hybridization studies although isoform-specific differences were observed. BAG-1L specific antibody showed ubiquitous staining as early as day 10.5 post-coitum but there was a progressive restriction during subsequent stages of embryogenesis. On the contrary, an antibody that preferentially recognized the other isoforms only stained the mouse myocardium in the early developmental stages before finally recognizing additional organs later on in development. These results demonstrate a stage- and site-specific expression of the BAG-1 isoforms during mouse development.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • COS Cells
  • Carrier Proteins / genetics*
  • DNA-Binding Proteins
  • Embryonic and Fetal Development
  • Gene Expression
  • Humans
  • Mice
  • Molecular Sequence Data
  • Protein Isoforms / genetics
  • RNA, Messenger
  • Transcription Factors


  • BCL2-associated athanogene 1 protein
  • Carrier Proteins
  • DNA-Binding Proteins
  • Protein Isoforms
  • RNA, Messenger
  • Transcription Factors