Identification of a mammalian homologue of the fungal Tom70 mitochondrial precursor protein import receptor as a Thyroid hormone-regulated gene in specific brain regions

• Published in: Journal of neurochemistry Vol. 73; no. 6; pp. 2240 - 2249
• Main Authors: ALVAREZ-DOLADO, M, GONZALEZ-MORENO, M, VALENCIA, A, ZENKE, M, BERNAL, J, MUNOZ, A
• Format: Journal Article
• Language: English
• Published: Oxford Blackwell 01.12.1999
• Subjects: Amino Acid Sequence; Animals; Base Sequence; Biological and medical sciences; Brain - metabolism; Endocrinopathies; Fungal Proteins - chemistry; Gene Expression Profiling; Gene Expression Regulation, Developmental - drug effects; Genes; Humans; Hypothyroidism - chemically induced; Hypothyroidism - metabolism; In Situ Hybridization; Medical sciences; Membrane Proteins - chemistry; Membrane Proteins - genetics; Membrane Proteins - isolation & purification; Membrane Proteins - physiology; Membrane Transport Proteins; Mitochondria - metabolism; Mitochondrial Membrane Transport Proteins; mitochondrial precursor protein; Mitochondrial Proteins; Molecular Sequence Data; Non tumoral diseases. Target tissue resistance. Benign neoplasms; Rats; Rats, Wistar; RNA, Messenger - biosynthesis; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae Proteins; Sequence Alignment; Sequence Homology, Amino Acid; Subtraction Technique; Thyroid Gland - physiology; Thyroid. Thyroid axis (diseases); Thyroxine - pharmacology; Endocrinopathy; Rat; Rodentia; Thyroid diseases; Homology; Corpus striatum; Identification; Hypothyroidism; Vertebrata; Experimental disease; Mammalia; Gene; Animal; Thyroid hormone
• DOI: 10.1046/j.1471-4159.1999.0732240.x
• ISSN: 0022-3042

Thyroid hormone is an important regulator of mammalian brain maturation. By differential display PCR, we isolated a cDNA clone (S2) that is specifically up-regulated in the striatum of neonatal hypothyroid rats. S2 was identified as KIAA0719, the first human gene distantly homologous to the fungal Tom70, which encodes a member of the translocase mitochondrial outer membrane complex involved in the import of preproteins into the mitochondria. By northern and in situ hybridization studies, KIAA0719 was found to be up-regulated in the striatum, nucleus accumbens, and discrete cortical layers of 15-day-old hypothyroid rats. In contrast, lower expression was found in the olfactory tubercle, whereas no differences were detected in other brain regions. Significantly, treatment of hypothyroid animals with single injections of thyroxine restored the normal levels of KIAA0719 expression. Moreover, treatment of control animals with thyroxine led to a reduced expression, demonstrating a negative hormonal regulation in vivo. Thus, KIAA0719 gene expression is regulated by thyroid hormone in the neonatal rat brain in a region-specific fashion. Given the role of the homologous Tom70 gene, the alteration of KIAA0719 expression may contribute to the changes in mitochondrial morphology and physiology caused by hypothyroidism in the developing rat brain.