Transforming growth factor-beta-activated kinase 1 (TAK1) has been linked to interleukin 1 receptor and tumor necrosis factor receptor signaling. Here we generated mouse strains with conditional expression of a Map3k7 allele encoding part of TAK1. TAK1-deficient embryonic fibroblasts demonstrated loss of responses to interleukin 1beta and tumor necrosis factor. Studies of mice with B cell-specific TAK1 deficiency showed that TAK1 was indispensable for cellular responses to Toll-like receptor ligands, CD40 and B cell receptor crosslinking. In addition, antigen-induced immune responses were considerably impaired in mice with B cell-specific TAK1 deficiency. TAK1-deficient cells failed to activate transcription factor NF-kappaB and mitogen-activated protein kinases in response to interleukin 1beta, tumor necrosis factor and Toll-like receptor ligands. However, TAK1-deficient B cells were able to activate NF-kappaB but not the kinase Jnk in response to B cell receptor stimulation. These results collectively indicate that TAK1 is key in the cellular response to a variety of stimuli.

Essential function for the kinase TAK1 in innate and adaptive immune responses.

The Cre/loxP system has become an important tool in designing postintegrational switch mechanisms for transgenes in mice. The power and spectrum of application of this system depends on transgenic mouse lines that provide Cre recombinase activity with a defined cell type-, tissue-, or developmental stage-specificity. We have developed a novel mouse line that acts as a Cre reporter. The mice, designated Z/EG (lacZ/EGFP), express lacZ throughout embryonic development and adult stages. Cre excision, however, removes the lacZ gene, which activates expression of the second reporter, enhanced green fluorescent protein. We have found that the double-reporter Z/EG line is able to indicate the occurrence of Cre excision from early embryonic to adult lineages. The advantage of the Z/EG line is that Cre-mediated excision can be monitored in live samples and that live cells with Cre-mediated excision can be isolated using a single-step FACS. It will be a valuable reagent for the increasing number of investigators taking advantage of the powerful tools provided by the Cre/loxP site-specific recombinase system.

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Z/EG, a double reporter mouse line that expresses enhanced green fluorescent protein upon Cre-mediated excision.

Melatonin, the major hormone produced by the pineal gland, displays characteristic daily and seasonal patterns of secretion. These robust and predictable rhythms in circulating melatonin are strong synchronizers for the expression of numerous physiological processes in photoperiodic species. In mammals, the nighttime production of melatonin is mainly driven by the circadian clock, situated in the suprachiasmatic nucleus of the hypothalamus, which controls the release of norepinephrine from the dense pineal sympathetic afferents. The pivotal role of norepinephrine in the nocturnal stimulation of melatonin synthesis has been extensively dissected at the cellular and molecular levels. Besides the noradrenergic input, the presence of numerous other transmitters originating from various sources has been reported in the pineal gland. Many of these are neuropeptides and appear to contribute to the regulation of melatonin synthesis by modulating the effects of norepinephrine on pineal biochemistry. The aim of this review is firstly to update our knowledge of the cellular and molecular events underlying the noradrenergic control of melatonin synthesis; and secondly to gather together early and recent data on the effects of the nonadrenergic transmitters on modulation of melatonin synthesis. This information reveals the variety of inputs that can be integrated by the pineal gland; what elements are crucial to deliver the very precise timing information to the organism. This also clarifies the role of these various inputs in the seasonal variation of melatonin synthesis and their subsequent physiological function.

Generation of the Melatonin Endocrine Message in Mammals: A Review of the Complex Regulation of Melatonin Synthesis by Norepinephrine, Peptides, and Other Pineal Transmitters

Hydrolysis and amino acid composition analysis of proteins

A transgenic mouse line that retains Cre recombinase activity in mature oocytes irrespective of the cre transgene transmission.

The methodologies for the analysis of D-amino acids in biological materials have been reviewed, including the use of enzymes, gas and liquid chromatography with chiral stationary phases and diastereomer derivatization with chiral reagents followed by GC or HPLC separation. The distribution of D-amino acids in the body, their origin, metabolism and possible roles in human diseases are discussed.

Kumiko Sakai

Papers

Analytical chemistry and biochemistry of D-amino acids

Localization of d-aspartic acid in elongate spermatids in rat testis

Emergence of D-aspartic acid in the differentiating neurons of the rat central nervous system.

Immunohistochemical localization of D-aspartate in the rat pineal gland.

D-Aspartic Acid Localization during Postnatal Development of Rat Adrenal Gland