ASEtrap: a biological method for speeding up the exploration of spliceomes.

Alternative splicing (AS) of pre-messenger RNA is a major mechanism for generating protein diversity from a limited number of genes in higher eukaryotes, and it constitutes a central mode of genetic regulation. Thus, efficient methods are needed to systematically identify new AS events at a genomic scale across different tissues, stages of development, and physiological or pathological conditions in order to better understand gene expression. To fulfill this goal, we have designed the ASEtrap, which is a cloning procedure for producing AS libraries that is based on a single-stranded trap consisting of an ssDNA-binding protein.

Targeted disruption of the type 2 selenodeiodinase gene (DIO2) results in a phenotype of pituitary resistance to T4.

The type 2 deiodinase (D2), a selenoenzyme that catalyzes the conversion of T4 to T3 via 5'-deiodination, is expressed in the pituitary, brain, brown adipose tissue (BAT), and the reproductive tract. To examine the physiological role of this enzyme, a mouse strain lacking D2 activity was developed using homologous recombination. The targeting vector contained the Neo gene in place of a 2.

Regulation of type 3 iodothyronine deiodinase expression in cultured rat astrocytes: role of the Erk cascade.

The type 3 iodothyronine deiodinase (D3) metabolizes thyroid hormones to inactive metabolites in many tissues, including the brain. In the present studies, we have examined the mechanisms by which T3 (T3), retinoic acid, 12-O-tetradecanoyl phorbol 13-acetate (TPA), and basic fibroblast growth factor (bFGF) induce D3 expression in primary cultures of neonatal rat astrocytes. In untreated cells, D3 messenger RNA (mRNA) was essentially undetectable by Northern analysis and RT-PCR.

Expression of the type II iodothyronine deiodinase in cultured rat astrocytes is selenium-dependent.

The iodothyronine deiodinases are a family of selenoproteins that metabolize thyroxine and other thyroid hormones to active and inactive metabolites in a number of tissues including brain. Using primary cultures of rat astroglial cells as a model system, we demonstrate that the mRNA for the type II iodothyronine deiodinase (DII) selenoenzyme is rapidly and markedly induced by forskolin and 8-bromo-cAMP. The induction of DII activity, however, was significantly impaired by culturing cells in selenium-deficient medium for 7 days.

Evidence that type III iodothyronine deiodinase in rat astrocyte is a selenoprotein.

A type III iodothyronine deiodinase (D-III) that inactivates thyroid hormones has been recently cloned and identified as a selenoprotein in neonatal rat skin. However, selenium (Se) deficiency does not affect the D-III activity in the rat placenta and decreases the D-III in the rat brain only slightly. This study examines the effect of Se on the D-III activity in cultures of rat brain astrocytes.