# A commonly used anti-SOX15 antibody fails to demonstrate specificity in mouse embryos

## TL;DR

A commonly used antibody for detecting SOX15 lacks specificity in mouse embryos, even when SOX15 is absent.

## Contribution

The study reveals that a commercially available anti-SOX15 antibody is not specific in mouse embryos.

## Key findings

- Nuclear signal was detected in both wild-type and Sox15-null embryos.
- The antibody's signal persisted even when maternal or paternal Sox15 contributions were eliminated.

## Abstract

SOX15 is a broadly conserved transcription factor involved in many critical processes, including mammalian cell fate specification and pluripotency. We investigated the specificity of a commercially available, polyclonal anti-SOX15 antibody advertised as knockout-validated. We generated a new mouse line carrying a null allele of

Sox15

, and then evaluated anti-SOX15 activity in

Sox15

null mouse embryos. Nuclear signal was detected in both wild type and null embryos, even when potential maternally or paternally-contributed

Sox15

was eliminated. We conclude that this SOX15-detecting reagent may not be suitable for all applications, and caution the growing community of users accordingly.