Transcriptional activation of the @entity1 glycoprotein hormone alpha-subunit (alphaGSU) promoter in response to @entity1176 and @entity1359 ( @entity4515 ) has been well characterized in alphaT3-1 gonadotropes but not investigated in the more differentiated LbetaT2 clonal gonadotrope. We have evaluated alphaGSU transcription in the more mature LbetaT2 cell line, using deletion and heterologous constructs of the alphaGSU promoter linked to a luciferase reporter gene. Basal alphaGSU-promoter activity was significantly less in LbetaT2 cells than in alphaT3-1 cells, but stimulation of transfected cells with @entity1176 and @entity4515 resulted in similar increases in alphaGSU-promoter activity. Deletional analysis of the @entity1 alphaGSU promoter in LbetaT2 cells indicated that sequences between -398 and -244 and between -244 and -195 base pairs (bp) were involved in regulating basal alphaGSU-promoter transcription, whereas the region between -244 and -195 bp regulated @entity4515 -stimulated promoter activity. Deletion of this promoter region containing a @entity25626 ) binding site abolished basal and @entity4515 -stimulated transcription. Site-directed mutagenesis of the @entity25626 binding site resulted in a significant attenuation of basal and @entity4515 -stimulated alphaGSU transcription. Pretreatment of LbetaT2 cells with a mitogen-activated protein kinase kinase-specific inhibitor, @entity5732 , abolished the @entity4515 -stimulated increase in MAPK activity and significantly reduced basal and @entity4515 -stimulated promoter activity. Electrophoretic mobility shift assays for @entity25626 and @entity10221 revealed that @entity4515 failed to affect @entity25626 binding but enhanced @entity10221 binding to a consensus @entity10221 oligonucleotide, an effect that was blocked with @entity5732 pretreatment, suggesting that @entity10221 may mediate ERK activation of alphaGSU transcription. Our data suggests that, in the mature LbetaT2 gonadotrope cell line, two regions of the @entity1 alphaGSU promoter regulate basal transcription and that @entity25626 is involved in mediating basal and @entity4515 -stimulated promoter activity. Furthermore, PKC-stimulated transcription partially relies on ERK acting on elements downstream of -244 bp of the @entity1 alphaGSU promoter.

Regulation of XXXX glycoprotein hormone alpha-subunit gene transcription in LbetaT2 gonadotropes by protein kinase C and extracellular signal-regulated kinase 1/2.

@entity1 :: ('9606', 'Species') :: ['human'] @entity5732 :: ('MESH:C113580', 'Chemical') :: ['U0126'] @entity4515 :: ('CHEBI:60755', 'Chemical') :: ['PMA'] @entity1359 :: ('CHEBI:37537', 'Chemical') :: ['phorbol-12-myristate-13-acetate'] @entity1176 :: ('MESH:D007987', 'Chemical') :: ['GnRH'] @entity10221 :: ('55278', 'Gene') :: ['GATA'] @entity25626 :: ('7536', 'Gene') :: ['SF-1', 'steroidogenic factor-1 (SF-1']
@entity1 :: (9606,Species) :: ['human']
