The accessibility of nascent polypeptides with special structural elements to the ribosome was investigated. Poly(C), poly(C, U) and poly(C, A) mRNAs were translated by E. coli ribosomes in vitro. The resulting peptides which were rich in prolines, remained on the ribosomal particles or were released after addition of puromycin. A protease from Aspergillus oryzae hydrolyzed the released peptides rapidly, whereas the degradation of the unreleased ones was only slightly affected. This result shows that the nascent peptides were protected against proteolytic attack by the ribosomal particles. Interestingly, the protease completely degraded the 30S particles whereas the 50S ones remained intact, even after prolonged incubation.
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The eukaryotic genome is broadly transcribed by RNA polymerase II (RNAPII) to produce protein-coding messenger RNAs (mRNAs) and a repertoire of non-coding RNAs (ncRNAs). Whereas RNAPII is very processive during mRNA transcription, it terminates rapidly during synthesis of many ncRNAs, particularly those that arise opportunistically from accessible chromatin at gene promoters or enhancers. The divergent fates of mRNA versus ncRNA species raise many questions about how RNAPII and associated machineries discriminate functional from spurious transcription.
View Article and Find Full Text PDFJMIR Ment Health
December 2024
Innovation Horizons, Inc., 2819 27th Street, NW, Washington, DC, US.
Background: Access to accurate medical diagnosis has been hindered by socioeconomic disparities, limited availability of specialized medical professionals, and lack of patient education, among other factors. Inequities in access to high-quality healthcare services exacerbate these challenges, often leading to disparities in health outcomes. Missed or inaccurate diagnoses can lead to delayed or unnecessary treatments, risking worsening of the condition.
View Article and Find Full Text PDFPublic Health Pract (Oxf)
June 2025
Instituto Nacional de Salud Pública, Morelos, Mexico.
Objectives: Movement behaviour research among preschoolers is nascent in low- and middle-income countries, where levels of physical activity, sleep, and sedentary behaviour in children are largely unknown. This study aimed to adapt and assess the acceptability and feasibility of the International Study of Movement Behaviours in the Early Years (SUNRISE) in Mexico, and report on challenges and solutions while implementing the protocol.
Study Design: Pilot study of the SUNRISE protocol in Mexico.
Nat Chem Biol
January 2025
Department of Gynecology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.
The regressed arms of reversed replication forks exhibit structural similarities to one-ended double-stranded breaks and need to be protected against uncontrolled nucleolytic degradation. Here, we identify MSANTD4 (Myb/SANT-like DNA-binding domain-containing protein 4), a functionally uncharacterized protein that uniquely counters the replication protein A (RPA)-Bloom (BLM)/Werner syndrome helicase (WRN)-DNA replication helicase/nuclease 2 (DNA2) complex to safeguard reversed replication forks from detrimental degradation, independently of the breast cancer susceptibility proteins (BRCA1/2)-DNA repair protein RAD51 pathway. MSANTD4 specifically interacts with the junctions between single-stranded DNA (ssDNA) and double-stranded DNA (dsDNA) in DNA substrates harboring a 3' overhang, which resemble the structural features of regressed arms processed by WRN-DNA2.
View Article and Find Full Text PDFLab Chip
January 2025
NASCENT Engineering Research Center, The University of Texas at Austin, Austin, Texas 78758, USA.
Despite being a high-resolution separation technique, deterministic lateral displacement (DLD) technology is facing multiple challenges with regard to design, manufacture, and operation of pertinent devices. This work specifically aims at alleviating difficulties associated with design and manufacture of DLD chips. The process of design and production of computer-aided design (CAD) mask layout files that are typically required for computational modeling analysis, optimization, as well as for manufacturing DLD-based micro/nanofluidic chips is complex, time-consuming, and often necessitates a high level of expertise in the field.
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