Interleukins (IL) 1 and 6 are important cytokines that function via the activation, respectively, of the transcription factors NF-B and STAT3. We have observed that a specific type of B DNA sequence motif supports both NF-B p65 homodimer binding and cooperativity with non-tyrosine-phosphorylated STAT3. This activity, in contrast to that mediated by B DNA motifs that do not efficiently bind p65 homodimers, is shown to be uniquely dependent upon signal transduction through the carboxyl terminus of TRAF6. Furthermore, STAT3 and p65 are shown to physically interact, in vivo, and this interaction appears to inhibit the function of "classical" STAT3 GAS-like binding sites. The distinct p50 form of NF-B is also shown to interact with STAT3. However, in contrast to p65, p50 cooperates with STAT3 bound to GAS sites. These data argue for a novel transcription factor cross-talk mechanism that may help resolve inconsistencies previously reported regarding the mechanism of IL-1 inhibition of IL-6 activity during the acute-phase response.

BackgroundTo characterize cathepsin K (CTSK) mutations in a group of patients with pycnodysostosis, who presented with either short stature or atypical fractures to pediatric endocrinology or dysmorphic features to pediatric genetics clinics.MethodsSeven exons and exon/intron boundaries of CTSK gene for the children and their families were amplified with PCR and sequenced. Sixteen patients from 14 families with pycnodysostosis, presenting with typical dysmorphic features, short stature, frequent fractures and osteosclerosis, were included in the study.ResultsWe identified five missense mutations (M1I, I249T, L7P, D80Y and D169N), one nonsense mutation (R312X) and one 301 bp insertion in intron 7, which is revealed as Alu sequence; among them, only L7P and I249 were described previously. The mutations were homozygous in all cases, and the families mostly originated from the region where consanguineous marriage rate is the highest. Patients with M1I mutation had fractures, at younger ages than the other pycnodysostosis cases in our cohort which were most probably related to the severity of mutation, since M1I initiates the translation, and mutation might lead to the complete absence of the protein. The typical finding of pycnodysostosis, acroosteolysis, could not be detected in two patients, although other patients carrying the same mutations had acroosteolysis. Additionally, none of the previously described hot spot mutations were seen in our cohort; indeed, L7P and R312X were the most frequently detected mutations.ConclusionsWe described a large cohort of pycnodysostosis patients with genetic and phenotypic features, and, first Alu sequence insertion in pycnodysostosis.

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