Alterations to DNA methylation and expression of CXCL14 are associated with suboptimal birth outcomes.

CXCL14 is a chemokine that has previously been implicated in insulin resistance in mice. In humans, the role of CXCL14 in metabolic processes is not well established, and we sought to determine whether CXCL14 is a risk susceptibility gene important in fetal programming of metabolic disease. For this purpose, we investigated whether CXCL14 is differentially regulated in human umbilical cords of infants with varying birth weights. We found an elevated expression of CXCL14 in human low birth weight (LBW) cords, as well as in cords from nutritionally restricted Macaca fascicularis macaques. To further analyze the regulatory mechanisms underlying the expression of CXCL14, we examined CXCL14 in umbilical cord-derived mesenchymal stem cells (MSCs) that provide an in vitro cell-based system amenable to experimental manipulation. Using both whole frozen cords and MSCs, we determined that site-specific CpG methylation in the CXCL14 promoter is associated with altered expression, and that changes in methylation are evident in LBW infant-derived umbilical cords that may indicate future metabolic compromise through CXCL14.

Galactose induction of the GAL1 gene requires conditional degradation of the Mig2 repressor.

Skp1 an essential component of the SCF (Skp1/cullin/F-box) E3 ubiquitin ligases, which target proteins for degradation by the 26S proteasome. We generated a skp1dM mutant strain that is defective for galactose induction of the GAL1 gene and we have found that galactose-induced protein degradation of the repressor Mig2 is defective in this strain. Mig2 degradation was also abolished in cells lacking the protein kinase Snf1 and the F-box protein Das1, suggesting that Snf1 triggers galactose-induced protein degradation of Mig2 by SCFDas1. Chromatin immunoprecipitation showed that Mig2 associates with the GAL1 promoter upon the galactose-induced exit of Mig1 in skp1dM cells, but not in wild-type cells, suggesting that the conditional degradation of Mig2 is required to prevent it from binding to the GAL1 promoter under inducing conditions. A galactose-stable deletion derivative of Mig2 caused a strong Mig (multi-copy inhibition of GAL gene expression) phenotype, confirming that galactose induction of the GAL1 gene requires the degradation of the repressor Mig2. Our results shed new light on the conflicting reports about the functional role of the degradation of transcriptional activators and indicate that gene expression studies interfering with proteasome degradation should take the stabilization of potential repressors into account.

Role of p63/p73 in epithelial remodeling and their response to steroid treatment in nasal polyposis.

BACKGROUND: Nasal polyposis (NP) is recognized as aberrant epithelial remodeling, but the molecular mechanism underlying this process is poorly understood. Two important p53 homologues (p63 and p73) play a key role in orchestrating the epithelial development. OBJECTIVE: We intended to study whether p63 and p73 are involved in the epithelial remodeling seen in patients with NP and their response to oral glucocorticosteroid (GC) treatment. METHODS: Nasal polyp tissues were obtained from 65 patients, and inferior turbinates were obtained from 19 control subjects without NP. Among patients with NP, 20 were treated with oral prednisone, so that 2 sets of polyp biopsy specimens were taken before (GC naive) and after (GC treated) treatment. Immunohistochemistry and quantitative PCR were performed to determine the expression levels of p63 and p73. RESULTS: The increase in p63-positive cell numbers was significant in GC-naive NP epithelium (46%) compared with that seen in control epithelium (5%), and it was positively related to the epithelial hyperplasia in patients with NP. The increase in N-terminal transactivation domain p73-positive cell numbers was found in 27% of GC-naive patients with NP and 16% of control subjects, with no statistical difference. The mRNA expression of both p63 and p73 was significantly upregulated in GC-naive patients with NP versus control subjects, and a positive correlation between the p63 and p73 mRNAs was found in all nasal tissues. Furthermore, the improvement of epithelial structure and reduction of p63 mRNA/protein levels were found in patients with NP after GC treatment. CONCLUSIONS: Our results suggest that the ectopic expression of p63 in multiple cell layers is an important pathologic phenomenon in the epithelial remodeling seen in chronically inflamed airway epithelium (eg, in patients with NP), and its aberrant expression can be suppressed with GC treatment.

Gal11p dosage-compensates transcriptional activator deletions via Taf14p.

Transcriptional activators work by recruiting transcription factors that are required for the process of transcription to their target genes. We have used the Split-Ubiquitin system to identify eight transcription factors that interacted with both the transcriptional activators Gal4p and Gcn4p in living cells. The over-expression of one of the activator-interacting proteins, Gal11p, partially suppressed GAL4 and GCN4 deletions. We have isolated two point mutants in Gal11p, F848L and F869S that were defective for the dosage compensation. We have identified 35 transcription factors that interacted with Gal11p in living cells, and the only protein-protein interaction affected by the Gal11p mutations was the one between Gal11p and Taf14p. We have further shown that the suppression of a GAL4 deletion by high levels of Gal11p required Taf14p, and that over-expression of Gal11p recruited Taf14p to the GAL1 promoter together with Tbp1p, Swi2p and Srb7p. Gal11p interacted with Mig1p, indicating that Mig1/2p could have recruited Gal11p to the GAL1 promoter in the absence of Gal4p. Our results suggest that transcriptional activators work by raising the local concentration of the limiting factor Gal11p, and that Gal11p works by recruiting Mediator and Taf14p-containing transcription factors like TFIID and SWI/SNF and by competing general repressors like Ssn6p-Tup1p off the target promoters.