Two papers by Siqian Feng

Editor's note:

Siqian Feng, a postdoc in the lab, has published two new papers recently.


July 06, 2022

Here is a very brief summary of two recent papers, published by Siqian Feng.

In the first paper, Siqian developed a new method that uses SpyTag-SpyCatcher technology to tag any protein of interest in vivo. All that is required is to first add the "SpyTag" peptide to a protein of interest using genome editing and, second, expressing "SpyCatcher" in cells of interest. When coexpressed, SpyCatcher forms a very specific covalent bond to SpyTag. If SpyCatcher is linked to some other protein (e.g. a fluorescent protein or an epitope for immunoprecipitation) then the protein of interest is now permanently fused to the SpyCatcher-fusion protein. Siqian used this to identify cell type-specific binding events of the transcription factor Ubx in the haltere imaginal disc, but we envision using it for many other applications where we want cell type-specific information.

In the second paper, Siqian used chromatin immunoprecipitation followed by deep sequencing (ChIP-seq) to compare the genome wide binding properties of two Drosophila Hox proteins (Scr and Ubx) in two serially homologous appendages -- the legs from the first thoracic segment (T1) and the legs from the third thoracic segment (T3). By making this comparison, Siqian was able to compare the amount of paralog-specific vs shared binding by these two Hox proteins and establish the roles of both previously known (Homothorax/Extradenticle) and novel (Distalless) Hox cofactors that contribute to their specific binding properties. Siqian also made a mutant allele of Scr that is no longer able to interact with Extradenticle to unambiguously identify Scr's Exd-dependent binding sites genome-wide.