Organization of the Mouse Ghrelin Gene and Promoter: Occurrence of a Short Noncoding First Exon

Tanaka, Minoru; Hayashida, Yukinobu; Iguchi, Tadashi; Nakao, Nobuhiro; Nakai, Norihiro; Nakashima, Kunio

doi:10.1210/endo.142.8.8433

Cited by 55 publications

(39 citation statements)

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“…Sequence analysis was performed on PCR products generated from multiple PIT and HPT cDNA samples. This analysis consistently revealed that, in the HPT and PIT, the dominant ghrelin transcript included In2, where the intron sequence differed from that originally reported by Tanaka et al (2001a; Genbank accession # AB060078) by 2 bp. Specifically, our sequence included eight TG nucleotides repeated in tandem in the middle of the In2 of the mouse ghrelin gene, starting at nucleotide position 1370 (Fig.…”

Section: Resultssupporting

confidence: 70%

Identification of a mouse ghrelin gene transcript that contains intron 2 and is regulated in the pituitary and hypothalamus in response to metabolic stress

Kineman

Gahete²,

Luque³

2007

Journal of Molecular Endocrinology

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The mouse ghrelin gene contains 5 exons (Ex), with Ex2-Ex5 encoding a 117 amino acid preproprotein that is processed to yield a 28 amino acid mature peptide. The current study examined if pituitary (PIT) and hypothalamus (HPT) ghrelin expression is up-regulated in response to fasting and down-regulated in obesity, as previously reported in the stomach. In the process of establishing a quantitative real-time RT-PCR system to accurately assess the changes in PIT and HPT ghrelin mRNA levels, we observed that primer sets located in Ex2 and Ex3 amplified a ghrelin transcript that contained the entire intron 2 (In2). Size and sequence analysis of RT-PCR products using multiple primer sets located throughout the ghrelin gene suggested that the In2-ghrelin variant contains Ex2 and Ex3, but lacks Ex1, Ex4, and Ex5. In2-ghrelin variant mRNA was not detected in stomach extracts, while expression levels were 10-and 50-fold greater than that of the native ghrelin transcript in the PIT and HPT respectively. In2-ghrelin variant mRNA levels increased in the PIT after 24 h fasting and decreased in the HPT and PIT of diet-induced obese mice. These changes may be due to the changes in circulating insulin or IGF-I, since both decreased In2-ghrelin variant expression in a mouse HPT cell line (N6) and in primary mouse PIT cell cultures. The fact that In2-ghrelin variant mRNA levels are dependent on energy intake in the PIT and HPT suggests that this transcript may encode a peptide important in coordinating the neuroendocrine response to metabolic stress.

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Section: Resultssupporting

confidence: 70%

Identification of a mouse ghrelin gene transcript that contains intron 2 and is regulated in the pituitary and hypothalamus in response to metabolic stress

Kineman

Gahete²,

Luque³

2007

Journal of Molecular Endocrinology

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“…This ghrelin transcript was composed of a distinct 68-bp sequence at the 5 0 -end, followed by a 252-bp sequence corresponding to exons 4 and 5 of the mouse ghrelin gene (Tanaka et al 2001). Notably, expression of 'full-length' ghrelin mRNA in the mouse testis was not detected in that study, using Northern hybridization.…”

Section: Rodent Datamentioning

confidence: 72%

“…The initial evidence for testicular expression of the ghrelin gene came from a study by Tanaka et al (2001), who identified a testis-specific ghrelin gene derived transcript in the mouse. This ghrelin transcript was composed of a distinct 68-bp sequence at the 5 0 -end, followed by a 252-bp sequence corresponding to exons 4 and 5 of the mouse ghrelin gene (Tanaka et al 2001).…”

Section: Rodent Datamentioning

confidence: 99%

Role of ghrelin in reproduction

García

López²,

Álvarez³

et al. 2007

Reproduction

106

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Ghrelin, the endogenous ligand of GH secretagogue receptor type 1a, has emerged as a pleiotropic modulator of diverse biological functions, including energy homeostasis and, lately reproduction. Here, we review recent reports evaluating the reproductive effects and sites of action of ghrelin, with particular emphasis regarding its role as a molecule integrating reproductive function and energy status. Data gleaned from rodent studies clearly show that besides having direct gonadal effects, ghrelin may participate in the regulation of gonadotropin secretion and it may influence the timing of puberty. In addition, experimental data showing that ghrelin and/or its receptor are expressed in normal human ovary and testis as well as in human ovarian and testicular tumors raise the possibility that the ghrelin system may be involved in the control of cell proliferation in these tumors. We propose that ghrelin either acting as an endocrine and/or paracrine signal may play a major role in the endocrine network that integrates energy balance and reproduction.

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“…DesGln 14 -ghrelin, a splice variant of ghrelin, is the second endogenous ligand for the GHS-R. Only a small percentage of the ghrelin clones isolated from the human stomach library encoded the des-Gln 14 -ghrelin precursor, and the des-Gln 14 -ghrelin peptide was not identified in human stomach. The ratios observed between the two precursor populations, ghrelin and des-Gln 14 -ghrelin, was 5 to 1 in rat stomach, and 6 to 5 in mouse stomach (24). These differences are likely species-specific.…”

Section: Figmentioning

confidence: 85%

“…O. and 0.05% NaN 3 ) containing 0.5% normal rabbit serum. The anti-rat ghrelin-(1-11) or anti-rat ghrelin- (13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28) antisera were used at final dilutions of 1:6,000,000 and 1:20,000, respectively. After incubation for 12 h, 100 l of 125 I-labeled tracer (15,000 cpm) was added.…”

Section: Methodsmentioning

confidence: 99%

Structural Divergence of Human Ghrelin

Hosoda¹,

Kojima²,

Mizushima³

et al. 2003

Journal of Biological Chemistry

283

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Ghrelin, a novel 28-amino acid peptide with an n-octanoyl modification at Ser 3 , was isolated from rat stomach and found to be an endogenous ligand for the growthhormone secretagogue receptor (GHS-R). This octanoyl modification is essential for ghrelin-induced GH release. We report here the purification and identification of human ghrelin from the stomach, as well as structural analysis of the human ghrelin gene and quantitation of changes in plasma ghrelin concentration before and after gastrectomy. Human ghrelin was purified from the stomach by gel filtration and high performance liquid chromatography, using a ghrelin-specific radioimmunoassay and an intracellular calcium influx assay on a stable cell line expressing GHS-R to test the fractions. In the course of purification, we isolated human ghrelin of the expected size, as well as several other ghrelin-derived molecules. Classified into four groups by the type of acylation observed at Ser 3 ; these peptides were found to be non-acylated, octanoylated (C8:0), decanoylated (C10:0), and possibly decenoylated (C10:1). All peptides found were either 27 or 28 amino acids in length, the former lacking the C-terminal Arg 28, and are derived from the same ghrelin precursor through two alternative pathways. The major active form of human ghrelin is a 28-amino acid peptide octanoylated at Ser 3 , as was found for rat ghrelin. Synthetic octanoylated and decanoylated ghrelins produce intracellular calcium increases in GHS-R-expressing cells and stimulate GH release in rats to a similar degree. Both ghrelin and the ghrelin-derived molecules were found to be present in plasma as well as stomach tissue. Plasma levels of immunoreactive ghrelin after total gastrectomy in three patients were reduced to approximately half of their pre-gastrectomy values, after which they gradually increased. This suggests that the stomach is the major source of circulating ghrelin and that other tissues compensate for the loss of ghrelin production after gastrectomy.

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Organization of the Mouse Ghrelin Gene and Promoter: Occurrence of a Short Noncoding First Exon

Cited by 55 publications

References 0 publications

Identification of a mouse ghrelin gene transcript that contains intron 2 and is regulated in the pituitary and hypothalamus in response to metabolic stress

Identification of a mouse ghrelin gene transcript that contains intron 2 and is regulated in the pituitary and hypothalamus in response to metabolic stress

Role of ghrelin in reproduction

Structural Divergence of Human Ghrelin

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