English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The POU-homeodomain transcription factor Pit-1 governs the pituitary cell-specific expression of Pit-1, GH, prolactin (PRL), and TSHß genes. Alternative splicing generates Pit-1ß, which contains a 26-amino acid ß-domain inserted at amino acid 48, in the middle of the Pit-1 transcription activation domain (TAD). Pit-1ß represses GH, PRL, and TSHß promoters in a pituitary-specific manner, because Pit-1ß activates these same promoters in HeLa nonpituitary cells. Here we comprehensively analyze the role of ß-domain sequence, position, and context, to elucidate the mechanism of ß-dependent repression. Repositioning the ß-motif to the Pit-1 amino terminus, hinge, linker, and carboxyl terminus did not affect its ability to repress basal rat (r) PRL promoter activity in GH4 pituitary cells, but all lost the ability to repress Ras-induced rPRL promoter activity. To determine whether ß-domain repression is independent of Pit-1 protein and DNA binding sites, we generated Gal4-Pit-1TAD, Gal4-Pit-1ßTAD, and Gal4-ß-domain fusions and demonstrated that the ß-motif is sufficient to actively repress VP16-mediated transcription of a heterologous promoter. Moreover, ß-domain point mutants had the same effect whether fused to Gal4 or within the context of intact Pit-1ß. Surprisingly, Gal4-ß repression lost histone deacetylase sensitivity and pituitary specificity. Taken together, these results reveal that the ß-motif is a context-independent, modular, transferable, and dominant repressor domain, yet the ß-domain repressor activity within Pit-1ß contains cell type, promoter, and Pit-1 protein context dependence.

The 26-Amino Acid ß-Motif of the Pit-1ß Transcription Factor Is a Dominant and Independent Repressor Domain