Biology subjects

Kreitzer, G.

Publications and source records attributed to Kreitzer, G..

2 recordsLinked to original sources

bioRxiv2025

The biochemical function of bivalent aptamer assemblies against B-cell markers CD19 and CD20

Aptamers are synthetic oligonucleotides that bind to their specific receptors with high specificity, offering immense potential for the development of molecular tools. Using recently introduced Ligand-Guided Selection (LIGS), a variant of the Systematic Evolution of Ligands by Exponential Enrichment (SELEX) we previously identified anti-CD19 and anti-CD20 aptamers with specificity and affinity. Given their high expression levels, B-cell markers CD19 and CD20 are widely utilized in the diagnosis of B-cell-related malignancies and autoimmune diseases. Here, we report the design and functional characterization of bivalent aptamer assemblies targeting CD19 and CD20 expressed in B-cell lymphomas. Using a strategic approach, we synthesized dimeric constructs of these aptamers with polyethylene glycol (PEG) linkers of varying lengths to tether the two aptamer units. The bivalent aptamers demonstrated enhanced binding affinity and specificity, with an optimal linker length of [~]3.96 nm. Functional studies revealed that dimeric CD19 aptamers selectively internalized in CD21-negative B-cells, while CD20 aptamers exhibited improved antigen binding without triggering calcium release. These findings highlight the potential of bivalent aptamers in engineering cost-effective, stable, and precise therapeutic agents for B-cell-related malignancies, such as diffuse large B-cell lymphoma (DLBCL). This work advances the development of aptamer-based synthetic therapeutics with promising clinical applications.

biochemistry↗

bioRxiv2022

Kinesin family motors modify transcription mediated by ERR1 using a conserved nuclear receptor box motif

Kinesin family motors are microtubule (MT)-stimulated ATPases known best as transporters of cellular cargoes through the cytoplasm, regulators of MT dynamics, organizers of the mitotic spindle, and for insuring equal division of DNA during mitosis. Several kinesins have also been shown to regulate transcription by interacting with transcriptional cofactors and regulators, nuclear receptors, or with specific promotor elements on DNA. We previously showed that an LxxLL nuclear receptor box motif in the kinesin-2 family motor KIF17 mediates binding to the orphan nuclear receptor estrogen related receptor alpha (ERR1) and is responsible for the suppression of ERR1-dependent transcription by KIF17. Analysis of all kinesin family proteins revealed that multiple kinesins contain this LxxLL motif, raising the question as to whether additional kinesins motors contribute to regulation of ERR1. In this study, we interrogated the effects of multiple kinesins with LxxLL motifs on ERR1-mediated transcription. We demonstrate that the kinesin-3 motor KIF1B contains two LxxLL motifs, one of which binds to ERR1. In addition, we show that expression of a KIF1B fragment containing this LxxLL motif inhibits ERR1-dependent transcription by regulating nuclear entry of ERR1. We also provide evidence that the effects of expressing the KIF1B-LxxLL fragment on ERR1 activity are mediated by a mechanism distinct from that of KIF17. Because LxxLL domains are found in many kinesins, our data suggest an expanded role for kinesins in nuclear receptor mediated transcriptional regulation.

cell biology↗