Development, Vol 112, Issue 4 1077-1093, Copyright © 1991 by Company of Biologists

JOURNAL ARTICLES

Phosphorylation, expression and function of the Ultrabithorax protein family in Drosophila melanogaster

ER Gavis and DS Hogness
Department of Biochemistry, Beckman Center, Stanford University School of Medicine, California 94305.

Alternative splicing of the Ultrabithorax homeotic gene transcript generates a family of five proteins (UBX isoforms) that function as transcription factors. All isoforms contain a homeodomain within a common 99 aa C-terminal region (C-constant region) which is jointed to a common 247 aa N-terminal (N-constant) region by different combinations of three small optional elements. Unlike the UBX proteins expressed in E. coli, UBX isoforms expressed in D. melanogaster cells are phosphorylated on serine and threonine residues, located primarily within a 53 aa region near the middle of the N-constant region, to form at least five phosphorylated states per isoform. Similar, if not identical states can be generated in vitro from purified E. coli UBX protein by a kinase activity in nuclear extracts from D. melanogaster cells. Temporal developmental profiles of UBX isoforms parallel those for the respective mRNAs, and all isoforms are similarly phosphorylated throughout embryogenesis. Analysis by cotransfection assays of the promoter activation and repression functions of mutant UBX proteins with various deletions in the N-constant region shows that repression is generally insensitive to deletion and, hence, presumably to phosphorylation. By contrast, the activation function is differentially sensitive to the different deletions in a manner indicating the absence of a discrete activating domain and instead, the presence of multiple activating sequences spread throughout the region.
CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter    What's this?

This article has been cited by other articles:

				Y. Yaron, J. K. McAdara, M. Lynch, E. Hughes, and J. C. Gasson Identification of Novel Functional Regions Important for the Activity of HOXB7 in Mammalian Cells J. Immunol., April 15, 2001; 166(8): 5058 - 5067. [Abstract] [Full Text] [PDF]

				C. V. Patel, R. Sharangpani, S. Bandyopadhyay, and P. E. DiCorleto Endothelial Cells Express a Novel, Tumor Necrosis Factor-alpha -regulated Variant of HOXA9 J. Biol. Chem., January 15, 1999; 274(3): 1415 - 1422. [Abstract] [Full Text] [PDF]

				H. Kasahara and S. Izumo Identification of the In Vivo Casein Kinase II Phosphorylation Site within the Homeodomain of the Cardiac Tisue-Specifying Homeobox Gene Product Csx/Nkx2.5 Mol. Cell. Biol., January 1, 1999; 19(1): 526 - 536. [Abstract] [Full Text] [PDF]

				A. Prokop and G. M. Technau Early tagma-specific commitment of Drosophila CNS progenitor NB1-1 Development, September 1, 1994; 120(9): 2567 - 2578. [Abstract] [PDF]

				S K Chan and R S Mann The segment identity functions of Ultrabithorax are contained within its homeo domain and carboxy-terminal sequences. Genes & Dev., May 1, 1993; 7(5): 796 - 811. [Abstract] [PDF]

				K. D. Irvine, J. Botas, S. Jha, R. S. Mann, and D. S. Hogness Negative autoregulation by Ultrabithorax controls the level and pattern of its expression Development, January 1, 1993; 117(1): 387 - 399. [Abstract] [PDF]