The 26-amino acid beta-motif of the Pit-1beta transcription factor is a dominant and independent repressor domain.

The POU-homeodomain transcription factor Pit-1 governs the pituitary cell-specific expression of Pit-1, GH, prolactin (PRL), and TSHbeta genes. Alternative splicing generates Pit-1beta, which contains a 26-amino acid beta-domain inserted at amino acid 48, in the middle of the Pit-1 transcription activation domain (TAD). Pit-1beta represses GH, PRL, and TSHbeta promoters in a pituitary-specific manner, because Pit-1beta activates these same promoters in HeLa nonpituitary cells.

Differential utilization of transcription activation subdomains by distinct coactivators regulates Pit-1 basal and Ras responsiveness.

The POU-homeodomain transcription factor Pit-1 governs ontogeny and cell-specific gene expression of pituitary lactotropes, somatotropes, and thyrotropes. The splice isoform, Pit-1beta, inserts a 26-amino acid (AA) repressor at AA48 in the Pit-1 transcription activation domain (TAD). The Pit-1 TAD contains a basal regulatory subregion, R1 (AA1-45), and a basal and Ras-responsive region, R2 (AA46-80).

Novel single-base deletional mutation in major intrinsic protein (MIP) in autosomal dominant cataract.

Purpose: To further elucidate the cataract phenotype, and identify the gene and mutation for autosomal dominant cataract (ADC) in an American family of European descent (ADC2) by sequencing the major intrinsic protein gene (MIP), a candidate based on linkage to chromosome 12q13.

Design: Observational case series and laboratory experimental study.

Methods: We examined two at-risk individuals in ADC2.

Pit-1beta reduces transcription and CREB-binding protein recruitment in a DNA context-dependent manner.

Many transcription factors are expressed as multiple isoforms with distinct effects on the regulation of gene expression, and the functional consequences of structural differences between transcription factor isoforms may allow for precise control of gene expression. The pituitary transcription factor isoforms Pit-1 and Pit-1beta differentially regulate anterior pituitary hormone gene expression. Pit-1 is required for the development of and appropriate hormone expression by anterior pituitary somatotrophs and lactotrophs.