21,606 research outputs found
Interactions between LHX3-And ISL1-family LIM-homeodomain transcription factors are conserved in Caenorhabditis elegans
No full text© 2017 The Author(s). LIM-Homeodomain (LIM-HD) transcription factors are highly conserved in animals where they are thought to act in a transcriptional 'LIM code' that specifies cell types, particularly in the central nervous system. In chick and mammals the interaction between two LIM-HD proteins, LHX3 and Islet1 (ISL1), is essential for the development of motor neurons. Using yeast two-hybrid analysis we showed that the Caenorhabditis elegans orthologs of LHX3 and ISL1, CEH-14 and LIM-7 can physically interact. Structural characterisation of a complex comprising the LIM domains from CEH-14 and a LIM-interaction domain from LIM-7 showed that these nematode proteins assemble to form a structure that closely resembles that of their vertebrate counterparts. However, mutagenic analysis across the interface indicates some differences in the mechanisms of binding. We also demonstrate, using fluorescent reporter constructs, that the two C. elegans proteins are co-expressed in a small subset of neurons. These data show that the propensity for LHX3 and Islet proteins to interact is conserved from C. elegans to mammals, raising the possibility that orthologous cell specific LIM-HD-containing transcription factor complexes play similar roles in the development of neuronal cells across diverse species
HomC(lim F (I), M) ≃ HomFun(I,C)(F, cM).
No full textThroughout this lecture, we let k denote an algebraically closed field, ℓ a prime number which is invertible in k. Let X be an algebraic curve over k and G a smooth affine group scheme over X whose generic fiber is semisimple and simply connected. Our goal over the next few lectures is to prove the following result: Theorem 1 (Nonabelian Poincare Duality). The forgetful functor ρ: RanG(X) → BunG(X) induces an isomorphism C∗(RanG(X); Zℓ) → C∗(BunG(X); Zℓ). Roughly speaking, our strategy will be to prove that ρ induces an isomorphism on Zℓ-homology by showing that the fibers of ρ are acyclic (with respect to Zℓ-homology). We begin with a few general remarks. Let C and I be categories, where I is small. For each object M ∈ C, let cM: I → C denote the constant functor with value M. If F: I → C is an arbitrary functor, then a colimit of F is an object lim F (I) ∈
The politics and economics of regulatory impact assessment
No full textThis is the author accepted manuscript. The final version is available from the publisher via the link in this record
LIM domain binding proteins 1 and 2 have different oligomeric states.
No full textLIM domain binding (Ldb) proteins are important regulators of LIM homeodomain and LIM-only proteins that specify cell fate in many different tissues. An essential feature of these proteins is the ability to self-associate, but there have been no studies that characterise the nature of this self-association. We have used deletion mutagenesis with yeast two-hybrid analysis to define the minimal self-association domains of Ldb1 and Ldb2 as residues 14–200 and 21–197, respectively. We then used a range of different biophysical methods, including sedimentation equilibrium and small-angle X-ray scattering to show that Ldb114–200 forms a trimer and Ldb221–197 undergoes a monomer–tetramer–octamer equilibrium, where the association in each case is of moderate affinity (105 M− 1). These modes of association represent a clear physical difference between these two proteins that otherwise appear to have very similar properties. The levels of association are more complex than previously assumed and emphasise roles of avidity and DNA looping in transcriptional regulation by Ldb1/LIM protein complexes. The abilities of Ldb1 and Ldb2 to form trimers and higher oligomers, respectively, should be considered in models of transcriptional regulation by Ldb1-containing complexes in a wide range of biological processes. © 2010, Elsevier Ltd
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