Biology subjects

Sadana, P.

Publications and source records attributed to Sadana, P..

2 recordsLinked to original sources

bioRxiv2026

Ribosome profiling reveals translational dynamics between an archaeal virus and its host

Host-virus interactions remain poorly understood in archaea, whose information processing systems harbor a mosaic of bacterial and eukaryotic features. Here, we used complementary multiomics to investigate interactions between Haloferax tailed virus 1 (HFTV1) and the halophilic archaeon Haloferax gibbonsii (Hg), capturing global translational and transcriptional dynamics across the infection cycle. This revealed co-regulatory expression patterns across HFTV1 and Hg genes. Post-transcriptional regulation was observed for several early HFTV1 genes and the late HFTV1 gene gp17, and the HFTV1 tRNA co-sedimented with Hg ribosome complexes. Infection reshaped the translational landscape of Hg, causing a slow decline in information processing activity, a complex transcriptional response, and amino acid starvation. An unannotated Tat-dependent fimbrial system of Hg was co-regulated with early HFTV1 genes and was correlated with increased biofilm formation, suggesting a potential antiviral defense system. These findings provide high-resolution insight into archaeal host-virus interactions at the evolutionary interface between bacteria and eukaryotes.

microbiology↗

bioRxiv2021

RIF1 acts in DNA repair through phosphopeptide recognition of 53BP1

The chromatin-binding protein 53BP1 promotes DNA repair by orchestrating the recruitment of downstream effectors including PTIP, RIF1 and shieldin to DNA double-strand break sites. While how PTIP recognizes 53BP1 is known, the molecular details of RIF1 recruitment to DNA damage sites remains undefined. Here, we report that RIF1 is a phosphopeptide-binding protein that directly interacts with three phosphorylated 53BP1 epitopes. The RIF1-binding sites on 53BP1 share an essential LxL motif followed by two closely apposed phosphorylated residues. Simultaneous mutation of these sites on 53BP1 abrogates RIF1 accumulation into ionizing radiation-induced foci, but surprisingly only fully compromises 53BP1-dependent DNA repair when an alternative mode of shieldin recruitment to DNA damage sites is also disabled. Intriguingly, this alternative mode of recruitment still depends on RIF1 but does not require its interaction with 53BP1. RIF1 therefore employs phosphopeptide recognition to promote DNA repair but also modifies shieldin action independently of 53BP1 binding.

molecular biology↗