ELUCIDATING PROP1 TRANSCRIPTIONAL COMPLEX THAT DIRECTS PITUITARY GLAND DEVELOPMENT

MERCOGLIANO FLORENCIA; SCHUSTER CLAUDIO; MARTI, MARCELO A.; PÉREZ MILLÁN, MARIA I.

Congreso; SAIC; 2020

Prop1 is the first pituitary specific transcription factor that leads gland development and lineage differentiation into the hormone-expressing cell types, but little is known about the regulation of this process. Our aim is to elucidate Prop1 transcriptional complex (TC) and the genes that are regulated to guide pituitary development. We used the murine pituitary cell line GHFT-1, engineered to express biotinylated Prop1, and conducted RNA-seq and RIME experiments. Differential gene expression analysis indicated that Prop1 upregulated 240 genes and downregulated 201 genes in Prop1 cell line compared to control (fold change=l1.5l). DAVID analysis showed that the most regulated GO terms were related to extracellular matrix, cell adhesion and junctions and positive regulation of proliferation and cell migration, among others. These results are in accordance with previous reports showing that Prop1 guides pituitary development through an EMT-like process.To study Prop1 TC we used RIME and identified 786 proteins that immunoprecipitated with Prop1. DAVID analysis showed enrichment in GO terms related to cell adherens junction, cadherin-binding involved in cell-cell adhesion, focal adhesion, RNA binding and splicing, spliceosome and chromatin binding. To further unveil Prop1 partners we used LISA which predicts transcriptional regulators using chromatin accessibility and histone mark ChIP-seq data. We used as input the genes that intersected from the ChIP and RNA-seq experiments and obtained 536 genes, DAVID analysis showed that the main GO terms were transcription regulation, in utero embryonic development, steroid hormone pathway, cell differentiation, chromatin remodeling and stem cells commitment, among others. Of these genes 37 were present in the RIME, i.e.: Stat3, Nfib, Sin3a and Ctnnb1. Further experimental work is needed to validate Prop1 interaction partners. Understanding the TC formed will shed light on the pivotal role of Prop1 in pituitary development.