Pit-1 Research Articles

A proline‐to‐histidine mutation in POU1F1 is associated with production traits in dairy cattle

POU class 1 homeobox 1 (POU1F1) is a member of the tissue-specific POU-containing transcription factor family. The expression of POU1F1 in mammalian pituitary gland controls the transcription of the genes encoding growth hormone, prolactin (PRL) and the subunits of thyroid-stimulating hormone. In addition, some genes in the JAK/STAT signalling pathway downstream of POU1F1 have been shown to be associated with different production traits in dairy cattle. To investigate whether the POU1F1 gene is associated with economically important traits in dairy cattle, a pooled DNA sequencing approach was used to identify single nucleotide polymorphisms (SNPs) in the gene. An SNP in exon 3 of POU1F1 that changes a proline to a histidine was identified. A total of 2141 individuals from two North American Holstein cattle resource populations were genotyped for this SNP using a modified PCR-RFLP method. Statistical analyses revealed significant association of POU1F1 variants with milk yield and productive life, which makes POU1F1 a possible candidate for marker-assisted selection in dairy cattle breeding programmes.

Polymorphisms of POU1F1 gene in 13/17 Robertsonian translocation pigs

Karyotype analysis was carried out by means of culturing whole peripheral blood from 394 pigs, which were produced from three hybridization combinations of 13/17 Robertsonian translocation pig. Three types of karyotype were detected in these hybrids, i.e., the homozygous pigs [2n=36, XY or XX, rob (13; 17)], the heterozygous pigs [2n=37, XY or XX, rob (13; 17)], and the normal karyotype pigs [2n=38, XY or XX]. A Rsa restriction enzyme polymorphic site in a 1 746 bp fragment of porcine POU1F1 gene was detected by PCR-RFLP analysis. While no mutation in exon 4 of porcine POU1F1 gene was detected by PCR-SSCP analysis in the hybrids of the three hybridization combinations. Population genetics analysis showed that for Rsa-RFLP, the frequencies of allele A and genotype AA were significantly higher than allele B and genotype BB in the three hybrid populations and the three type of karyotype populations. The frequency of genotype AB was higher in the heterozygous translocation population than in the other two karyotype populations. Chi-square test suggested that all the populations did not reach Hardy-Weinberg equilibrium. The progeny populations of heterozygous 13/17 translocation pig x heterozygous 13/17 translocation pig, heterozygous 13/17 translocation pig x Yorkshire, and heterozygous pig population had medium polymorphism and others had low polymorphism.

Basic science and clinical research advances in the pituitary transcription factors: Pit-1 and Prop-1

The pituitary-specific transcription factors, Pit-1 (also called Pou1f1) and prophet of Pit-1 (Prop-1), are critical for normal pituitary development and function. The aim of the present review is to highlight the recent basic science and clinical research advances in these transcription factors, as they relate to signaling pathway interactions, gene regulation, and mutations in human diseases. A number of important basic research discoveries have been made in the area of the pituitary-specific transcription factors, Pit-1 and Prop-1. Among these findings include: the effects of the Pit-1 coactivators, GATA-2 and TRAP-220, on the transcriptional regulation of the TSHbeta gene and thyrotropin expression, characterization of a novel pituitary regulator of Pit-1 expression, Atbf1, elucidation of the roles of Wnt and Notch signaling on Prop-1-mediated specification of the Pit-1 cell lineage and gonadotropes, and the identification of regulatory regions of the Prop-1 gene. Advances in clinical research include: the identification of novel mutations in the human POU1F1 and PROP-1 genes, and screening guidelines for patients with combined pituitary hormone deficiencies and possible mutations in these transcription factors. Research into the complex interplay of signaling pathways and transcription factors that regulate the pituitary gland are important areas of developmental biology and normal physiology. Clinically, such research has important implications for human diseases by identifying inheritable transcription factor mutations that may cause pituitary hormonal deficiencies.

A PstI polymorphism at 3′UTR of goat POU1F1 gene and its effect on cashmere production

POU1F1 is a positive regulator for prolactin (PRL) whose metabolites may directly or indirectly affect some aspects of the hair growth cycle, therefore, POU1F1 gene is an important candidate gene for cashmere traits selection through marker-assisted selection (MAS). Hence, in this study, the PCR-RFLP method was applied to detect a T>C transition determining a PstI polymorphism at the 3'UTR of POU1F1 locus and evaluate its associations with cashmere traits in 847 Inner Mongolia White Cashmere goats. In the analyzed population, the allelic frequencies for the T and C alleles are 0.959 and 0.041, respectively and the genotypic frequencies are in Hardy-Weinberg equilibrium (P > 0.05). Moreover, significant statistical relationships between the PstI polymorphism of POU1F1 gene and goat cashmere yields were found (*P < 0.05). When compared with TC genotype, TT genotype was associated with superior cashmere yields in 2, 4, and 5 years old individuals, as well as with average cashmere yield. Hence, TT genotype is suggested to be a molecular marker for senior cashmere yield.

Genetic effects of &lt;I&gt;MC4R&lt;/I&gt; and &lt;I&gt;POU1F1 &lt;/I&gt;gene on the growth performance in Jinghai yellow chicken

Melanocortin-4 receptor (MC4R) gene and pituitary specific transcription factor 1 (POU1F1) gene were studied as candidate genes on the Jinghai yellow chicken in this study. Polymorphisms of MC4R and POU1F1 gene had been analyzed by PCR-SSCP and DNA sequencing method. The relationship between two candidate genes and the growth performance of Jinghai yellow chicken had also been analyzed by GLM model. The frequency of A/B alleles for MC4R gene in the population was 0.929 and 0.071, and that of C/D alleles for POU1F1 gene was 0.500 and 0.500. The results showed that AA genotype of MC4R gene had higher bodyweight at 4, 8, 12 weeks compared to AB and BB genotype (P<0.05); CD genotype of POU1F1 gene had significantly higher bodyweight at all weeks compared to CC and DD genotype (P<0.01). So, it could be preliminarily deduced that MC4R and POU1F1 gene were probably the major gene on growth performance or a QTL linked gene which associated with growth performance in chicken.

A TaqI PCR-RFLP Detecting a Novel SNP in Exon 2 of the Bovine POU1F1 Gene

PCR-SSCP and DNA sequencing methods were applied to reveal three novel single nucleotide polymorphisms (SNPs) in exon 2 of the POU1F1 gene in 963 Chinese cattle belonging to eight breeds. Among them, a silent SNP (NM_174579:c.545G > A) detected by TaqI endonuclease is described. Frequencies of the POU1F1-G allele varied from 0.685 to 1.000. The association of TaqI polymorphism with growth traits was analyzed in 251 Nanyang cattle. No significant associations of the TaqI polymorphism with body weight and average daily gain for different growth periods (6, 12, 18, and 24 months old) were observed (P > 0.05), as well as for body sizes (P > 0.05).

Analysis of caprine pituitary specific transcription factor-1 gene polymorphism in indigenous Chinese goats

Since mutations on POU1F1 gene possibly resulted in deficiency of GH, PRL, TSH and POU1F1, this study revealed the polymorphism of goat POU1F1-AluI locus and analyzed the distribution of alleles on 13 indigenous Chinese goat breeds. The PCR-RFLP analysis showed the predominance of TT genotype and the frequencies of allele T varied from 0.757 to 0.976 in the analyzed populations (SBWC, Bo, XH and HM). Further study, distributions of genotypic and allelic frequencies at this locus were found to be significantly different among populations based on a chi(2)-test (P < 0.001), suggesting that the breed factor significantly affected the molecular genetic character of POU1F1 gene. The genetic diversity analysis revealed that Chinese indigenous populations had a wide spectrum of genetic diversity in goat POU1F1-AluI locus. However, the ANOVA analysis revealed no significant differences for gene homozygosty, gene heterozygosty, effective allele numbers and PIC (polymorphism information content) among meat, dairy and cashmere utility types (P > 0.05), suggesting that goat utility types had no significant effect on the spectrum of genetic diversity.

Polymorphisms in intron 1 of the porcinePOU1F1 gene

This study was conducted to detect polymorphisms in intron 1 of porcine POU1F1 (POU domain, class 1, transcription factor 1, Pit1, renamed as POU1F1) by comparative sequencing. Within the intron, 23 sites of variation were identified, including 16 single-nucleotide substitutions, 4 single-nucleotide indels, 2 short (3-bp and 17-bp), and one long (313-bp) indels. Several important regulatory motifs were found within the 313-bp indel by in silico analysis. The 313-bp indel was next genotyped in 11 Chinese native pig breeds and 4 western meat-type pig breeds. The appearance of genotypes varied between breeds: among Chinese native breeds, no AA and AB genotypes were found in Tibetan, Lingao, Min, Rongchang, and Songliao Black pigs, no AA genotype was found in Fenjing and Leping Spotted pigs, whereas in Pietrain and Landrace there were no BB genotypes, and all 19 Duroc pigs were AA homozygotes. The western meat-type pigs had high A allele frequencies and the Chinese pigs had more B alleles, except Jianquhai pigs. A positive association of the AA genotype with birth weight was observed in a commercial pig line. This paper demonstrated that the genetic variation in intron 1 of the pig POU1F1 gene was high and these polymorphisms may provide useful makers for QTL analysis.

DdeI Polymorphism in Coding Region of Goat POU1F1 Gene and Its Association with Production Traits

POU1F1 is a positive regulator for GH, PRL and TSHβ and its mutations associate with production traits in ruminant animals. We described a Ddel PCR-RFLP method for detecting a silent allele in the goat POU1F1 gene: TCT (241Ser)>TCG (241Ser). Frequencies of D 1 allele varied from 0.600 to 1.000 in Chinese 801 goats. Significant associations of Ddel polymorphism with production traits were found in milk yield (*p<0.05), litter size (*p<0.05) and one-year-old weight (*p<0.05) between different genotypes. Individuals with genotype D 1 D 1 had a superior performances when compared to those with genotype D 1 D 2 (*p<0.05). Hence, the POU1F1 gene was suggested to the potential candidate gene for superior milk performance, reproduction trait and weight trait. Genotype D 1 D 1, characterized by a Ddel PCR-RFLP detection, was recommended to geneticists and breeders as a molecular marker for better performance in the goat industry.

Polymorphism of the Bovine POU1F1 Gene: Allele Frequencies and Effects on Milk Production in Three Iranian Native Breeds and Holstein Cattle of Iran

The aim of this study was to estimate the allele frequencies in polymorphic site of exon six of POU1F1 gene in three Iranian native and Holstein cattle. Genomic DNA was extracted from 3 Iranian native cattle breeds, including 97 Mazandarani, 87 Sarabi, 112 Golpaygani and also 110 Holstein cattle. A 451 bp fragment of intron 5 and exon 6 were amplified and digested with HinfI restriction enzyme. Frequencies of allele A were 0.37, 0.27, 0.34 and 0.21 for Mazandarani, Sarabi, Golpaygani and Holstein cattle, respectively. Significant differences in genotype frequencies were found between Mazandarani or Golpaygani and Holstein cattle. No significant differences in genotype frequencies were found between Sarabi and Holstein cattle. Transition A to G in nucleotide 1256 is responsible for HinfI(-) allele. No significant association was observed between POU1F1 polymorphism and milk production. Differences in allelic frequency between native Bos indicus breeds (Mazandarani, Golpaygani) and Holstein at the present study might be due to differences in origin breeds, low number of samples and/or as the effect of natural selection in native breeds.

A DdeI PCR-RFLP detecting genetic variation of goat POU1F1 gene

We described a DdeI PCR-RFLP method for detecting silent allele at goat POU1F1 locus: p.S241S. Frequencies of D1 allele varied from 0.600 to 1.000 in eight Chinese native breeds. Association of DdeI RFLP genotypes with milk yield of dairy goat was significant (P &lt; 0.05). Key words: Goat, POU1F1 gene, polymorphism, association, milk yield

An AluI PCR-RFLP detecting a silent allele at the goat POU1F1 locus and its association with production traits

Here, we firstly described an AluI PCR-RFLP method for detecting a silent allele at goat POU1F1 locus: AG T (279Ser) to AG C (279Ser). Frequencies of POU1F1-C allele in the analyzed populations varied from 0.000 to 0.523 in 801 samples belonging to nine native goat breeds in China. The association between genotypes (TT and TC) and 11,026 records of eight production traits was analyzed in 663 samples. Significant statistical associations results were found in milk yield ( * P < 0.05) and birth weight ( * P < 0.05), which implied that POU1F1 gene had a positive effect on milk performance and early weight trait. While goat POU1F1 gene did not exert significant effect on hair traits. Hence, we firstly suggested that genotype TC and TT could be regarded as molecular markers for superior milk yield and birth weight in goat, respectively.

Effect of Genetic Variations of the POU1F1 Gene on Growth Traits of Nanyang Cattle

PCR-RFLP was applied to analyze the effect of the genetic variations of the POU1F1 gene on growth traits of 100 Nanyang cattle. The results showed that the 451 bp PCR product digested with Hinf I demonstrated polymorphism in the population, which was at Hardy-Weinberg equilibrium. Moreover, the frequencies of alleles A/B in the Nanyang population were 0.465/0.535. The association of the variations of the POU1F1 gene with the growth traits in the population was analyzed. The following parameters were greater in individuals with a genotype BB than in those with an genotype AB: birth weight, average weight increase before ablactation, body height at 12 months, body weight, body length, and chest girth at 6 months and 12 months ( P<0.05). The body weight at 12 months was higher in the BB individuals than in the AA individuals ( P <0.05). The body weight and body sizes also showed a trend of allele B> allele A in the other age groups. Therefore, the genotype BB maybe a dominant genotype and the allele B may be a dominant allele. These results imply that the allele B of the POU1F1 gene is likely to positively affect the growth traits.

Identification and Functional Analysis of the Novel S179R POU1F1 Mutation Associated with Combined Pituitary Hormone Deficiency

The pituitary-specific transcription factor 1 plays a key role in the development and differentiation of three pituitary cell types: somatotrophs, lactotrophs, and thyrotrophs. Several mutations of the human gene (called POU1F1) have been shown to be responsible for a phenotype of combined pituitary hormone deficiency involving GH, prolactin (PRL), and TSH. We have identified a novel homozygous C to G mutation in exon 4 of the POU1F1 gene (S179R) in a patient with this rare phenotype. We analyzed the functional consequences of this S179R mutation associated with a single-amino acid change in the POU-specific domain. Consequences of this mutation on transcriptional activities by transfection studies in alphaT3 cells, DNA binding ability by EMSA, structural properties, and nuclear accumulation of POU1F1 were investigated. The transactivation capacity of this mutant was markedly decreased on the GH1, PRL, TSHbeta, and POU1F1 genes. Interestingly, this mutation abolished the functional interaction of POU1F1 on the PRL promoter with the coactivator cAMP response element-binding protein-binding protein but not with the transcription factor LIM homeodomain transcription factor 3. The S179R mutant displayed normal nuclear accumulation but a markedly decreased binding to a DNA response element in keeping with crystallographic data, suggesting that the S179R mutation might interfere with DNA binding. Together with previous data, our study indicates that both DNA binding and interaction with cofactors like cAMP response element-binding protein-binding protein are critical for POU1F1 function and that functional and structural properties of abnormal POU1F1 proteins are variously influenced by the type of mutations.

Identification and characterization of four splicing variants of ovine POU1F1 gene

Expression of POU1F1 gene, a member of the POU homeodomain family of transcription factors, is necessary for normal differentiation, development and survival of three anterior pituitary cell types (thyrotrophs, somatotrophs and lactotrophs) and for the proper expression of growth hormone ( GH), prolactin ( PRL), thyroid-stimulating hormone ( TSH) genes and POU1F1 gene itself. Alternative splicing forms of this gene have been reported in different species, with few functional studies. Apart from the POU1F1-Wild-type with the expected length, in this work we isolated three additional splicing variants: POU1F1-β, with a 78 bp insert in the trans-activation domain; POU1F1-γ that lacks exon 3 and POU1F1-δ that lacks exons 3, 4 and 5. Four different protein isoforms were also detected by Western blot in the sheep pituitary tissue. Functional assays were performed to study the trans-activation of GH and PRL promoters by the splicing variants. Regarding the PRL promoter, the β variant presented only 12% of the Wild-type trans-activation capacity. Variants γ and δ showed no capacity to trans-activate PRL promoter. Both γ and δ variants acted as repressors of Wt, reducing significantly the trans-activation made by Wt alone ( p < 0.05). Concerning the GH promoter, the β variant presented a trans-activation capacity 10% higher than Wt. Wt and β variants strongly interact in the activation of GH promoter doubling the trans-activation potential of Wt. Variants γ and δ showed no capacity to trans-activate the GH promoter and both acted as repressors, reducing significantly ( p < 0.001) the trans-activation performed by Wt. This work presents, for the first time, the characterization of four splicing forms of Ovis aries POU1F1 gene.

Genetic Screening of Combined Pituitary Hormone Deficiency: Experience in 195 Patients

Mutations in transcription factors result in combined pituitary hormone deficiency (CPHD). A genetic screening strategy, based on endocrine and neuroradiological phenotype according to published knowledge, was applied to establish the prevalence of gene defects in each category of patients and provide a useful framework for clinicians to determine the genetic etiology and recurrence risks for individuals and families. One hundred ninety-five CPHD patients from the international GENHYPOPIT network were studied, according to their phenotype, for POU1F1, PROP1, LHX3, LHX4, and HESX1. Patients selected had two pituitary hormone deficiencies or at least one deficiency with intracerebral malformations. Total prevalence of mutations was 13.3 and 52.4% in 20 patients with familial CPHD history. No mutation of HESX1 was observed in 16 patients harboring septooptic dysplasia. A mutation of LHX4 gene, previously reported, was found in one familial case from 39 patients bearing pituitary stalk interruption syndrome. In 109 patients without extrapituitary abnormalities, 20 had PROP1 mutations, including eight patients with a family history of CPHD. Among 20 patients without pituitary stalk interruption syndrome, no LHX3 gene defect was found, even with a neck rotation deficit. One POU1F1 gene defect was found in one patient presenting the rare postpubertal association of thyrotroph (TSH deficiency) and somatotroph (GH deficiency) deficits. Mutation of PROP1 gene remains the first to be looked for, and POU1F1 mutations should be sought in GH deficiency and TSH deficiency postpubertal population without extrapituitary malformations. Identification of gene defects allows early treatment of any deficit and prevention of their potentially fatal consequences. Genotyping appears highly beneficial at an individual and familial level.

Ovis aries POU1F1 Gene: Cloning, Characterization and Polymorphism Analysis

POU1F1 (PIT-1/GHF-1) is a transcription factor with critical role in the transcriptional regulation of multiple genes in the pituitary and also important for the survival, differentiation and proliferation of three pituitary cell types. To understand the regulation of POU1F1 gene in Ovis aries we report its cloning, sequencing and characterization. The sequenced 5787 bp included six exons and two complete introns. Ovine POU1F1 gene has a high level of conservation with its bovine, human and rat counterparts showing 98.2%, 91.2% and 86.2% of similarity at the coding level, respectively. All six exons were analyzed for polymorphism detection in 100 animals of the Portuguese indigenous ovine breed 'Churra da Terra Quente'. One polymorphism was found at codon 58 in exon 2, in one allele of 4 animals leading to a change from cysteine to tyrosine (2% allelic frequency). In exon 3 two polymorphisms were detected: a G to A transition altering a glycine to an asparagine at codon 89 in one allele of one animal (0.5% allelic frequency) and another G to A transition at codon 105 converting an alanine into a threonine in one allele of 3 animals (1.5% allelic frequency). These polymorphisms might change the structure of the POU1F1 protein and modify gene-expression. In intron 4, an A to G transition was detected in one allele of six animals (3% allelic frequency). Exons 1, 4 and 6 showed no polymorphisms.

Positive association between POU1F1 and mental retardation in young females in the Chinese Han population

Genetic defects attributable to the genes involved in the hypothalamus-pituitary-thyroid (HPT) gland axis can cause abnormal thyroid hormone function and mental retardation (MR). Pit-1, encoded by the POU1F1 gene on human chromosome 3p11, is a pituitary-specific transcription factor responsible for the expression of several pituitary hormones. Thyrotropin is one of these hormones and is an important regulator in the HPT axis. One of the symptoms of patients with POU1F1 mutations is hypothyroidism and abnormalities of the nervous system early in the period after birth. We performed a case-control association study and a quantitative analysis of IQ to investigate the possible genetic contribution of POU1F1 in the Chinese Han population. Pairwise linkage disequilibrium (LD) analysis showed that rs300996, snp-7057 and rs300977 were in strong LD. There were significant differences of allele, genotype and haplotype frequencies of these three single nucleotide polymorphisms (SNPs) between cases and controls. When we conducted a breakdown comparison between cases and controls within different gender groups, no positive results in males were found. In females, however, we found significant differences between cases and controls in allele frequency distribution of rs300996 (P=0.0003), snp-7057 (P=0.0001) and rs300977 (P=0.0005) and in the distributions of common haplotypes combined by these SNPs (global P=0.0050). The P-value was 0.0301 for rs300996 and 0.0397 for the haplotype combination of rs300996-snp-7057-rs300977 in the analysis of the quantitative effects of the alleles and haplotypes on IQ in females. Our data suggest that POU1F1 may affect MR through a gender-specific mechanism.

Analysis of POU1F1 Gene Polymorphisms in Qinchuan Cattle and Chinese Holstein Cattle

PCR-RFLP was applied to analyze the polymorphisms of POU1F1 gene in 218 Qinchuan cattle (QQ) and Chinese Holstein cattle (HC). Results demonstrated Hinf I polymorphisms in the 451 bp PCR product in the two populations. The frequencies of alleles A/B in QQ and HC populations were 0.232/0.768 and 0.132/0.868, respectively. The frequencies of three genotypes AA, AB and BB were 0.030/0.403/0.567 and 0.007/0.251/0.742, respectively. Qinchuan cattle population was at Hardy-Weinberg equilibrium at this locus, but Chinese Holstein cattle population was not. The gene heterozygosity/effective allele gene number/Shannon information entropy/polymorphism information content of Qinchuan cattle and Chinese Holstein cattle populations were listed for 0.356/1.553/0.541/0.292 and 0.229/1.297/0.390/0.203, respectively. All indices were higher in the Qinchuan cattle population.

Auxological and endocrine phenotype in a population-based cohort of patients with PROP1 gene defects

Multiple pituitary hormone deficiency (MPHD) may result from defects of transcription factors that govern early pituitary development. We aimed to establish the prevalence of HESX1, PROP1, and POU1F1 gene defects in a population-based cohort of patients with MPHD and to analyse the phenotype of affected individuals. Genomic analysis was carried out on 74 children and adults with MPHD from the Czech Republic (including four sibling pairs). Phenotypic data were collected from medical records and referring physicians. One patient carried a heterozygous mutation of POU1F1 (71C > T), and 18 patients (including three sibling pairs) had a PROP1 mutation (genotypes 150delA/301delGA/9/, 301delGA/301-delGA/8/, or 301delGA/349T > A/1/). A detailed longitudinal phenotypic analysis was performed for patients with PROP1 mutations (n = 17). The mean ( +/-s.d.) birth length SDS of these patients (0.12 +/- 0.76) was lower than expected based on their mean ( +/-s.d.) birth weight SDS (0.63 +/- 1.27; P = 0.01). Parental heights were normal. The patients' mean ( +/-s.d.) height SDS declined to -1.5 +/- 0.9, -3.6 +/- 1.3 and -4.1 +/- 1.2 at 1.5, 3 and 5 years of age, respectively. GH therapy, initiated at 6.8 +/- 3.2 years of age (mean dose: 0.022 mg/kg per day), led to substantial growth acceleration in all patients. Mean adult height (n = 7) was normal when adjusted for mid-parental height. ACTH deficiency developed in two out of seven young adult patients. PROP1 defects are a prevalent cause of MPHD. We suggest that testing for PROP1 mutations in patients with MPHD might become standard practice in order to predict risk of additional pituitary hormone deficiencies.