RESUMEN
Autoimmune myelofibrosis (AIMF) is an uncommon cause of myelofibrosis associated with favorable outcome. Primary AIMF, AIMF without a known systemic autoimmune disorder, has been described in adults, but never in children. Here, we present, for the first time, an apparent case of primary AIMF in a 15-year-old boy admitted with profound hypoproliferative anemia.
RESUMEN
Promoters are DNA elements that enable transcription and its regulation by trans-acting factors. Here, we demonstrate that yeast promoters can also regulate mRNA decay after the mRNA leaves the nucleus. A conventional yeast promoter consists of a core element and an upstream activating sequence (UAS). We find that changing UASs of a reporter gene without altering the transcript sequence affects the transcript's decay kinetics. A short cis element, comprising two Rap1p-binding sites, and Rap1p itself, are necessary and sufficient to induce enhanced decay of the reporter mRNA. Furthermore, Rap1p stimulates both the synthesis and the decay of a specific population of endogenous mRNAs. We propose that Rap1p association with target promoter in the nucleus affects the composition of the exported mRNP, which in turn regulates mRNA decay in the cytoplasm. Thus, promoters can play key roles in determining mRNA levels and have the capacity to coordinate rates of mRNA synthesis and decay.
