Biology subjects

Hobor, F.

Publications and source records attributed to Hobor, F..

3 recordsLinked to original sources

bioRxiv2022

Held out wings RNA binding activity in the cytoplasm during early spermatogenesis

Held out wings (HOW) is an RNA-binding protein essential for spermatogenesis in Drosophila melanogaster. HOW is a signal transduction and activation of RNA (STAR) protein, regulating post-transcriptional gene expression. The characteristics of RNA-binding by the conserved short cytoplasmic isoform, HOW(S), are unknown. In vivo RIP-seq identified 121 novel transcripts bound by HOW(S) in germ stem cells and spermatogonia, many with signal transduction functions. (A/G/U)CUAAC motifs were enriched in 3-UTRs and GCG(A/U)G in 5-UTRs. HOW binds with high-affinity to sites containing CUAAC motifs from lola and hipk mRNAs. This study provides new insight into STAR protein-RNA interactions and functions in spermatogenesis.

molecular biology↗

bioRxiv2021

Understanding p300-transcription factor interactions using sequence variation and hybridization

The hypoxic response is central to cell function and plays a significant role in the growth and survival of solid tumours. HIF-1 regulates the hypoxic response by activating over 100 genes responsible for adaptation to hypoxia, making it a potential target for anticancer drug discovery. Although there is significant structural and mechanistic understanding of the interaction between HIF-1 and p300 alongside negative regulators of HIF-1 such as CITED2, there remains a need to further understand the sequence determinants of binding. In this work we use a combination of protein expression, chemical synthesis, fluorescence anisotropy and isothermal titration calorimetry for HIF-1 sequence variants and a HIF-1- CITED hybrid sequence which we term CITIF. We show the HIF-1 sequence is highly tolerant to sequence variation through reduced enthalpic and less unfavourable entropic contributions, These data imply backbone as opposed to side chain interactions and ligand folding control the binding interaction and that sequence variations are tolerated as a result of adopting a more disordered bound interaction or "fuzzy" complex.

biochemistry↗

bioRxiv2019

Selective Affimers Recognize BCL-2 Family Proteins Through Non-Canonical Structural Motifs

The BCL-2 family is a challenging set of proteins to target selectively due to sequence and structural homologies across the family. Selective ligands for the BCL-2 family regulators of apoptosis are desirable as probes to understand cell biology and apoptotic signalling pathways, and as starting points for inhibitor design. We have used phage display to isolate Affimer reagents (non-antibody binding proteins based on a conserved scaffold) to identify ligands for MCL-1, BCL-xL, BCL-2, BAK and BAX, then used multiple biophysical characterisation methods to probe the interactions. We established that purified Affimers elicit selective and potent recognition of their target BCL-2 protein. For anti-apoptotic targets, competitive inhibition of their canonical protein-protein interactions is demonstrated. Co-crystal structures reveal an unprecedented mode of molecular recognition; where a BH3 helix is normally bound, flexible loops from the Affimer dock into the BH3 binding cleft. Moreover, the Affimers induce a change in the target proteins towards a desirable drug bound like conformation. These results indicate Affimers can be used as alternative templates to inspire design of selective BCL-2 family modulators, and provide proof-of-concept for the elaboration of selective non-antibody binding reagents for use in cell-biology applications.

biochemistry↗