Expression of gap-junctional protein (connexin 43 or alpha 1 gap junction) is down-regulated at the transcriptional level during adipocyte differentiation of H-1/A marrow stromal cells.

Bone marrow stromal cells are requisite for the proliferation of hematopoietic cells and communicate with each other via gap junctions. Marrow stromal cells expressed connexin 43, but not connexin 32. H-1/A, a murine marrow stromal cell line, underwent adipocyte differentiation at confluence, and expressed the 3.0 kilobase mRNA species of connexin 43 before differentiation. H-1/A cells studied with the dye-transfer method showed gap-junctional communication with adjacent cells but lost this communication during differentiation. The connexin 43 transcripts in H-1/A cells were down-regulated before the expression of glycero-monophosphate dehydrogenase was induced. Loss of gap-junctional communication was regulated at the mRNA level of connexin 43. Connexin 43 expression was down-regulated at the transcriptional level.