The highly condensed chromosomes and chromosome breaks in mitotic cells of a Drosophila mutant, spotted-dick/pita, are the consequence of defects in DNA replication. Reduction of levels of Spotted-dick protein, by either RNAi or mutation, leads to the accumulation of cells that have DNA content intermediate to 2N and 4N in proliferating tissues and also compromises endoreduplication in larval salivary glands. The Spotted-dick Zinc-finger protein is present in the nuclei of cells committed to proliferation but necessary in cells undertaking S phase. We show that Spotted-dick/Pita functions as a transcription factor and that, in cultured S2 cells, it is an activator of expression of some 30 genes that include the Orc4 gene, required for initiation of DNA replication. Chromatin immunoprecipitation indicates that it associates with the genes that it activates in S2 cells together with other sites that could represent genes activated in other tissues. We discuss the role of Spotted-dick in the coordination of cellular growth and DNA replication.
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http://dx.doi.org/10.1038/sj.emboj.7600890 | DOI Listing |
Hum Mol Genet
January 2025
Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, 83 Fenyang Road, Xuhui District, Shanghai 200031, China.
Primary open-angle glaucoma (POAG), known as a common ocular disease with genetic heterogeneity, is characterized by progressive optic disc atrophy and visual field defects. This study aimed to assess the contribution of previously reported POAG-associated genes and investigate potential functional variations and genotype-phenotype correlations in a Han Chinese population. DNA from 500 cases and 500 controls was pooled and sequenced using a customized panel of 398 candidate genes.
View Article and Find Full Text PDFJ Biochem
January 2025
Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
For bidirectional replication in E. coli, higher-order complexes are formed at the replication origin oriC by the initiator protein DnaA, which locally unwinds the left edge of oriC to promote the loading of two molecules of DnaB onto the unwound region via dynamic interactions with the helicase-loader DnaC and the oriC-bound DnaA complex. One of the two helicases must translocate rightwards through oriC-bound DnaA complex.
View Article and Find Full Text PDFTheor Appl Genet
January 2025
Plant Breeding, Wageningen University and Research, Wageningen, The Netherlands.
The tomato Ty-6 gene conferring resistance against begomoviruses has been cloned and shown to be a variant of DNA polymerase delta subunit 1. Ty-6 is a major resistance gene of tomato that provides resistance against monopartite and bipartite begomoviruses. The locus was previously mapped on chromosome 10, and in this study, we fine-mapped Ty-6 to a region of 47 kb, including four annotated candidate genes.
View Article and Find Full Text PDFNat Metab
January 2025
State Key Laboratory of Natural Medicines, School of Life Science and Technology, China Pharmaceutical University, Nanjing, China.
Nucleotide availability is crucial for DNA replication and repair; however, the coordinating mechanisms in vivo remain unclear. Here, we show that the circadian clock in the liver controls the activity of the pentose phosphate pathway (PPP) to support de novo nucleotide biosynthesis for DNA synthesis demands. We demonstrate that disrupting the hepatic clock by genetic manipulation or mistimed feeding impairs PPP activity in male mice, leading to nucleotide imbalance.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Département de Biologie, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada.
To achieve replicative immortality, cancer cells must activate telomere maintenance mechanisms. In 10 to 15% of cancers, this is enabled by recombination-based alternative lengthening of telomeres pathways (ALT). ALT cells display several hallmarks including heterogeneous telomere length, extrachromosomal telomeric repeats, and ALT-associated PML bodies.
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