The human growth hormone gene contains both positive and negative control elements

Area of Science:

• Molecular Biology
• Genetics
• Biochemistry

Background:

• The 5'-flanking region of the human growth hormone (hGH) gene contains regulatory sequences controlling its expression.
• Understanding these sequences is crucial for deciphering gene regulation mechanisms.

Purpose of the Study:

• To investigate protein-DNA interactions and functional roles of cis-acting elements in the hGH gene's 5'-flanking region.
• To identify transcription factors that bind to these regulatory elements and their impact on gene expression.

Main Methods:

• Protein-DNA binding assays were employed to detect factor interactions with hGH DNA.
• Gene transfer and expression experiments in HeLa cells were used to assess the functional impact of identified elements.

Main Results:

• Two adjacent cis-acting elements (I and II) located between nucleotides -308/-235 of the hGH gene were identified.
• Elements I and II repressed reporter gene expression, while element II alone demonstrated activation.
• Two distinct factors (Factor I and Factor II) were found to bind hGH DNA; Factor I binds single-stranded DNA and is linked to repression, while Factor II binds a region homologous to the adenovirus major late transcription factor binding site.

Conclusions:

• The hGH gene promoter contains regulatory elements that modulate its expression.
• A shared transcription regulatory element exists between the hGH and adenovirus major late promoters, involving Factor II binding.
• These findings provide insights into the complex regulation of hGH gene expression and potential cross-talk with viral gene regulation pathways.