Chloroplast transcription in land plants relies on collaboration between a plastid-encoded RNA polymerase (PEP) of cyanobacterial ancestry and a nucleus-encoded RNA polymerase of phage ancestry. PEP associates with additional proteins that are unrelated to bacterial transcription factors, many of which have been shown to be important for PEP activity in Arabidopsis (Arabidopsis thaliana). However, the biochemical roles of these PEP-associated proteins are not known. We describe phenotypes conditioned by transposon insertions in genes encoding the maize (Zea mays) orthologs of five such proteins: ZmPTAC2, ZmMurE, ZmPTAC10, ZmPTAC12, and ZmPRIN2. These mutants have similar ivory/virescent pigmentation and similar reductions in plastid ribosomes and photosynthetic complexes. RNA gel-blot and microarray hybridizations revealed numerous changes in plastid transcript populations, many of which resemble those reported for the orthologous mutants in Arabidopsis. However, unanticipated reductions in the abundance of numerous transfer RNAs (tRNAs) dominated the microarray data and were validated on RNA gel blots. The magnitude of the deficiencies for several tRNAs was similar to that of the most severely affected messenger RNAs, with the loss of trnL-UAA being particularly severe. These findings suggest that PEP and its associated proteins are critical for the robust transcription of numerous plastid tRNAs and that this function is essential for the prodigious translation of plastid-encoded proteins that is required during the installation of the photosynthetic apparatus.
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http://dx.doi.org/10.1104/pp.113.228726 | DOI Listing |
Am J Perinatol
December 2024
The People's Hospital of Shanxi Province, Taiyuan, Shanxi Province, China.
Objective: Septic acute lung injury (ALI) is a common complication of sepsis with high morbidity and mortality but lacks specific treatment. This study aimed to elucidate the role of circular RNA TLK1 (circTLK1) in neonatal septic ALI.
Study Design: Murine cecal slurry was used to induce neonatal sepsis-induced ALI model in vivo.
Pathol Res Pract
December 2024
Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, 1300 York Ave, New York, NY 10065, USA; Englander Institute for Precision Medicine, Weill Cornell Medicine, 413 East 69th Street, New York, NY 10021, USA. Electronic address:
Pancreatic acinar cell carcinoma (PACC) is a rare pancreatic tumor with a heterogeneous clinical course and, except for radical surgery, limited treatment options. We present a comprehensive study encompassing whole-genome and RNA sequencing of 7 tumor samples from 3 metastatic PACC patients to further delineate its genomic landscape and potential therapeutic implications. Our findings reveal distinct signatures of homologous recombination deficiency (HRD) in patients harboring pathogenic germline BRCA1/2 and FANCL mutations, demonstrating favorable responses to poly (ADP-ribose) polymerase 1 (PARP) inhibitors with prolonged disease-free intervals.
View Article and Find Full Text PDFVirulence
December 2025
Key Laboratory of Avian Bioproducts Development, Ministry of Agriculture and Rural Affairs, Yangzhou, China.
Several viruses, including influenza A virus (IAV), encode viral factors to hijack cellular RNA biogenesis processes to direct the degradation of host mRNAs, termed "host shutoff." Host shutoff enables viruses to simultaneously reduce antiviral responses and provides preferential access for viral mRNAs to cellular translation machinery. IAV PA-X is one of these factors that selectively shuts off the global host genes.
View Article and Find Full Text PDFNew Phytol
December 2024
State Key Laboratory of Wheat Improvement, College of Life Science, Shandong Agricultural University, Tai'an, 271018, China.
Protoderm formation is a crucial step in early embryo patterning in plants, separating the precursors of the epidermis and the inner tissues. Although key regulators such as ARABIDOPSIS THALIANA MERISTEM LAYER1 (ATML1) and PROTODERMAL FACTOR2 (PDF2) have been identified in the model plant Arabidopsis thaliana, the genetic pathways controlling protoderm specification remain largely unexplored. Here, we combined genetic, cytological, and molecular approaches to investigate the regulatory mechanisms of protoderm specification in Arabidopsis thaliana.
View Article and Find Full Text PDFJ Transl Med
December 2024
Department of Pediatric Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Jiefang Avenue, Wuhan, 430022, Hubei Province, People's Republic of China.
Background: Neuroblastoma (NB), the most prevalent solid tumor in children, arises from sympathetic nervous system and accounts for 15% of pediatric cancer mortality. This malignancy exhibits substantial genetic and clinical heterogeneity, thus complicating treatment strategies. Poly(ADP-ribose) polymerase 1 (PARP1), a key enzyme catalyzing polyADP-ribosylation (PARylation), plays critical roles in various cellular processes, and contributes to tumorigenesis and aggressiveness.
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