Grtp1, A Novel Gene Regulated by Growth Hormone

• Published in: Endocrinology (Philadelphia) Vol. 142; no. 10; pp. 4568 - 4571
• Main Authors: Lu, Chunxia, Kasik, John, Stephan, Dietrich A, Yang, Shaohua, Sperling, Mark A, Menon, Ram K
• Format: Journal Article
• Language: English
• Published: United States Endocrine Society 01-10-2001; Oxford University Press
• Subjects: Amino Acid Sequence; Amino acids; Animals; Base Sequence; Cells, Cultured; Chromosome 8; DNA microarrays; Gene expression; Gene Expression Regulation - drug effects; Growth Hormone - pharmacology; Growth hormones; Humans; Intestine; Kidneys; Liver; Mice; Molecular Sequence Data; mRNA; Organ Specificity; Protein arrays; Proteins; rab GTP-Binding Proteins - drug effects; rab GTP-Binding Proteins - genetics; Rats; Testes
• ISSN: 0013-7227; 1945-7170
• DOI: 10.1210/endo.142.10.8527

An in vitro model of GH-responsive cells was subjected
to microarray analysis to identify a novel gene regulated by GH. This
258 amino acid protein, we term GH
Regulated TBC Protein-1
(GRTP1), contains the TBC signature motif of GTPase activator
proteins of Rab-like small GTPases. Northern blot analysis revealed a
1.3 kb major mRNA species, most abundant in testes. TaqMan assay
confirmed that in the mouse, Grtp1 is expressed at
highest levels in testes, with lesser abundance in intestine, kidney,
lung, and liver. In the testis, expression of Grtp1
significantly increases post-pubertally. Administration of GH to mice
increased levels of GRTP1 mRNA in testes (140%), but decreased GRTP1
mRNA abundance in kidney (50%) and liver (25%). Grtp1
was localized to mouse proximal chromosome 8. Orthologs of this protein
are present in human, mouse, rat, and drosophila suggesting that GRTP1
has an important biological role(s).