Journal Article
Rauskolb, C, Pan G, Reddy BVVG, Oh H, Irvine KD.  2011.  Zyxin links fat signaling to the hippo pathway. PLoS Biology. 9:e1000624. AbstractWebsite
The Hippo signaling pathway has a conserved role in growth control and is of fundamental importance during both normal development and oncogenesis. Despite rapid progress in recent years, key steps in the pathway remain poorly understood, in part due to the incomplete identification of components. Through a genetic screen, we identified the Drosophila Zyxin family gene, Zyx102 (Zyx), as a component of the Hippo pathway. Zyx positively regulates the Hippo pathway transcriptional co-activator Yorkie, as its loss reduces Yorkie activity and organ growth. Through epistasis tests, we position the requirement for Zyx within the Fat branch of Hippo signaling, downstream of Fat and Dco, and upstream of the Yorkie kinase Warts, and we find that Zyx is required for the influence of Fat on Warts protein levels. Zyx localizes to the sub-apical membrane, with distinctive peaks of accumulation at intercellular vertices. This partially overlaps the membrane localization of the myosin Dachs, which has similar effects on Fat-Hippo signaling. Co-immunoprecipitation experiments show that Zyx can bind to Dachs and that Dachs stimulates binding of Zyx to Warts. We also extend characterization of the Ajuba LIM protein Jub and determine that although Jub and Zyx share C-terminal LIM domains, they regulate Hippo signaling in distinct ways. Our results identify a role for Zyx in the Hippo pathway and suggest a mechanism for the role of Dachs: because Fat regulates the localization of Dachs to the membrane, where it can overlap with Zyx, we propose that the regulated localization of Dachs influences downstream signaling by modulating Zyx-Warts binding. Mammalian Zyxin proteins have been implicated in linking effects of mechanical strain to cell behavior. Our identification of Zyx as a regulator of Hippo signaling thus also raises the possibility that mechanical strain could be linked to the regulation of gene expression and growth through Hippo signaling.
Brown, BA, Padgett RW, Hardies SC, Hutchison CA, Edgell MH.  1982.  β-globin transcript found in induced murine erythroleukemia cells is homologous to the beta h0 and beta h1 genes. Proceedings of the National Academy of Sciences of the United States of America. 79:2753-7. AbstractWebsite
RNA transcripts complementary to at least one of the four beta-globin homologous genes (beta h) are found in high concentration in the murine erythroleukemic (MEL) cell line GM979 after butyric acid induction. Hybridization data indicate that the gene expressed is Hbb-beta h0 or Hbb-beta h1, or both. The level of beta h0/1 transcripts in the MEL cell is similar to the level of adult transcripts. The Hbb-beta h0/1 transcript is about 800 nucleotides in length. In addition, there is a larger beta h0/1 transcript of the same size and relative intensity as the adult beta-globin precursor. We also report significant levels of embryonic gene Hbb-y transcripts in induced GM979 cells. We have determined that the GM979 cell line has the [Hbb]s haplotype on the basis of an examination of its globin DNA restriction pattern. An additional MEL cell line of haplotype [Hbb]d (DBA/2 line 6A11A) was examined and found to contain no significant level of Hbb-beta h0, Hbb-beta h1, Hbb-beta h2, or Hbb-y gene transcripts.