RNA helicase A (RHA) is a member of an ATPase/DNA and RNA helicase family and is a homologue of Drosophila maleless protein (MLE), which regulates X-linked gene expression. RHA is also a component of holo-RNA polymerase II (Pol II) complexes and recruits Pol II to the CREB binding protein (CBP). The ATPase and/or helicase activity of RHA is required for CREB-dependent transcription. To further understand the role of RHA on gene expression, we have identified a 50-amino-acid transactivation domain that interacts with Pol II and termed it the minimal transactivation domain (MTAD). The protein sequence of this region contains six hydrophobic residues and is unique to RHA homologues and well conserved. A mutant with this region deleted from full-length RHA decreased transcriptional activity in CREB-dependent transcription. In addition, mutational analyses revealed that several tryptophan residues in MTAD are important for the interaction with Pol II and transactivation. These mutants had ATP binding and ATPase activities comparable to those of wild-type RHA. A mutant lacking ATP binding activity was still able to interact with Pol II. In CREB-dependent transcription, the transcriptional activity of each of these mutants was less than that of wild-type RHA. The activity of the double mutant lacking both functions was significantly lower than that of each mutant alone, and the double mutant had a dominant negative effect. These results suggest that RHA could independently regulate CREB-dependent transcription either through recruitment of Pol II or by ATP-dependent mechanisms.RNA helicase A (RHA) is a member of the DExH family of ATPases/helicases and catalyzes the displacement of both double-stranded RNA and DNA from 3Ј to 5Ј (32,61,63). Functional domains of RHA include two double-stranded RNA binding domains at the amino terminus known as dsRBD1 and dsRBD2. The catalytic core domain is located within the central region and contains a DExH motif. This core domain contains seven well-conserved motifs; one of them has an ATP binding site with the consensus GCGKT and FILDD, known as the A site the B site, respectively. The carboxyl terminus contains an RGG-rich region that is capable of binding singlestrand nucleic acids (62).RHA was originally isolated as a human homologue of Drosophila maleless protein (MLE), with which it has 50% sequence identity and 90% sequence similarity (33). In Drosophila, MLE colocalizes with acetylated histone H4 (8, 48). MLE is involved in sex-specific gene dosage compensation and elevates the level of transcription derived from a single X chromosome in male flies to a level equivalent to that derived from two X chromosome in the female (25,29). MLE mutants are embryonic lethal to males, indicating that MLE is an essential factor in Drosophila development.In mammals, RHA-knockout mice are embryonic lethal for homozygous RHA mutants (35). Analysis of these mice revealed that RHA is associated with differentiation of the embryonic ectoderm during gastrulation. It is possible that RHA has an i...
RNA helicase A (RHA)1 catalyzes the unwinding of duplex RNA and DNA in a process coupled with the hydrolysis of NTPs (1, 2). We have previously shown that RHA mediates association of the CREB-binding protein (CBP) with RNA polymerase II (pol II) (3) and that RHA links breast cancer-specific tumor suppressor protein (BRCA1) to pol II (4). RHA consists of two type A double-stranded RNA-binding domains (dsRBDs) (5, 6), a classical Walker type NTP-binding site, a DEAH/D helicase domain, and a single-stranded nucleic acid-binding domain characterized by Arg-Gly-Gly (RGG) repeats (7). Trypsin-digested RHA, lacking both dsRBDs and the RGG repeat sequence, has reduced helicase activity, implicating these domains in the unwinding function of RHA (7). Amino acids 1-262 and 255-664 of RHA have proved to be CBP-and pol II-binding sites, respectively (3). RHA shuttles between nucleus and cytoplasm with a cis-acting constitutive transport element in simian retroviruses (8). It has been proposed that RHA is necessary for releasing both constitutive transport element-and HIV-1 Rev response element (RRE)-containing RNA from spliceosomes prior to the completion of splicing (9).
We investigated the clinical course of individuals with 2019 novel coronavirus disease (COVID-19) who were transferred from the Diamond Princess cruise ship to 12 local hospitals. The conditions and clinical courses of patients with pneumonia were compared with those of patients without pneumonia. Among 70 patients (median age: 67 years) analyzed, the major symptoms were fever (64.3%), cough (54.3%), and general fatigue (24.3%). Forty-three patients (61.4%) had pneumonia. Higher body temperature, heart rate, and respiratory rate as well as higher of lactate dehydrogenase (LDH), aspartate aminotransferase (AST), and C-reactive protein (CRP) levels and lower serum albumin level and lymphocyte count were associated with the presence of pneumonia. Ground-glass opacity was found in 97.7% of the patients with pneumonia. Patients were administered neuraminidase inhibitors (20%), lopinavir/ritonavir (32.9%), and ciclesonide inhalation (11.4%). Mechanical ventilation and veno-venous extracorporeal membrane oxygenation was performed on 14 (20%) and 2 (2.9%) patients, respectively; two patients died. The median duration of intubation was 12 days. The patients with COVID-19 transferred to local hospitals during the outbreak had severe conditions and needed close monitoring. The severity of COVID-19 depends on the presence of pneumonia. High serum LDH, AST and CRP levels and low serum albumin level and lymphocyte count were found to be predictors of pneumonia. It was challenging for local hospitals to admit and treat these patients during the outbreak of COVID-19. Assessment of severity was crucial to manage a large number of patients.
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