Michael Grunstein (born 1946 in Romania) is a Professor of Biological Chemistry at the David Geffen School of Medicine at UCLA.Grunstein pioneered the genetic analysis of histones in yeast and showed for the first time that histones are regulators of gene activity in living cells. His studies were among the most influential to counter the prevailing belief in the 1980s that eukaryotic genes, like previously studied bacterial genes, were predominantly subjected to transcriptional activation.He received Rosenstiel Award in 2010 for their discovery that histones and histone acetylation directly regulate transcription.