POU Domain, Class 1, Transcription Factor 1

Alternative Names

POU1F1
Pituitary-Specific Transcription Factor 1
PIT1
Growth Hormone Factor 1
GHF1

Associated Diseases

Pituitary Hormone Deficiency, Combined, 1

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OMIM Number

173110

Gene Map Locus

3p11.2

Description

The POU1F1 gene is mapped to chromosome 3p11.2, where it encodes a 33 kDa pituitary-specific transcription factor present in somatotrophs, lactotrophs and thyrotrophs of the mature pituitary. The embryonal expression of POU1F1 precedes that of GH and (TSH)b. POU1F1 is responsible for pituitary development and hormone expression by activating growth hormone and prolactin genes. Specifically, it binds to the consensus sequence 5'-TAAAT-3' of these genes.

Defects in this protein are the cause of combined pituitary hormone deficiency 1, a condition characterized by pleiotropic deficiencies of growth hormone, prolactin and thyroid-stimulating hormone, while the production of adrenocorticotropic hormone, luteinizing hormone, and follicle-stimulating hormone are preserved.

Molecular Genetics

The POU1F1 gene consists of six coding exons, and spans approximately 17 kb in the genomic DNA. The PIT1 protein has a size of around 32 KDa and is made up of 291 amino acids. Mutations in this gene have been identified in patients with combined pituitary hormone deficiency.

Epidemiology in the Arab World

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Other Reports

Palestine

Gat-Yablonski et al. (2002) described a novel mutation in the PIT-1 gene in a consanguineous Arab family affected with Combined Pituitary Hormone Deficiency. This missense mutation (p.G688A) caused a lysine to glutamic acid substitution at a conserved position in the first helix of the POU homeodomain. Gat-Yablonski et al. (2002) considered it likely that the substitution would disrupt the DNA-binding activity of the protein.

Saudi Arabia

Pernasetti et al. (1998) carried out mutation screening for the POU1F1 gene in seven children with combined pituitary hormone deficiency from Saudi Arabia. A novel homozygous T>C transversion mutation in exon six was identified in all affected children. The mutation is located at a strictly conserved residue at the beginning of the second alpha-helix of the POU homeodomain and results in a p.P239S amino acid substitution. The DNA binding properties of the mutant POU1F1 protein were unaltered, but it was unable to stimulate transcription.

External Links

http://ghr.nlm.nih.gov/gene/POU1F1 http://www.genecards.org/cgi-bin/carddisp.pl?gene=POU1F1

Contributors

Ghazi O. Tadmouri: 01.12.2014
Pratibha Nair: 09.09.2014
Nada Assaf: 02.09.2014

Edit History

Pratibha Nair: 11.12.2014
Pratibha Nair: 07.12.2014