0000000001055373
AUTHOR
Maria Rapp
A differential role of CREB phosphorylation in cAMP-inducible gene expression in the rat pineal
In the rat pineal gland cAMP mediates nocturnal induction of the enzyme arylalkylamine N-acetyltransferase (AA-NAT) as well as of transcription factors such as inducible cAMP early repressor (ICER), Fos-related antigen-2 (Fra-2) and JunB. Cyclic AMP stimulates the phosphorylation of the DNA binding protein cAMP response element binding protein (CREB). While cAMP-induced CREB phosphorylation appears to be a prerequisite for AA-NAT and ICER gene expression, it is not known whether CREB phosphorylation accounts for the full cAMP response of the two genes. Furthermore, the significance of CREB phosphorylation in cAMP-activated Fra-2 and JunB transcription is unknown. In the present in vitro stu…
Serine/Threonine Phosphatase Inhibitors Decrease Adrenergic Arylalkylamine N -Acetyltransferase Induction in the Rat Pineal Gland
Adrenergic regulation of the pineal enzyme serotonin N-acetyltransferase [arylalkylamine N-acetyltransferase (AA-NAT); EC 2.3.1.87] accounts for the circadian rhythm in melatonin formation. In the present study, the role of protein phosphatases in the adrenergic regulation of rat pineal AA-NAT was investigated using specific inhibitors. In cultured pineals, the serine/threonine phosphatase type 1 and type 2A inhibitors okadaic acid and calyculin A significantly decreased adrenergically or cAMP-induced AA-NAT activity, whereas the serine/threonine phosphatase type 2B inhibitor cypermethrin and tyrosine phosphatase inhibitor dephostatin were ineffective. Reverse transcriptase-polymerase chain…
Focal Transcriptional Activity of Murine Cytomegalovirus during Latency in the Lungs
ABSTRACT Interstitial pneumonia is a frequent and critical manifestation of human cytomegalovirus (CMV) disease in immunocompromised patients, in particular in recipients of bone marrow transplantation. Previous work in the murine CMV infection model has identified the lungs as a major organ site of CMV latency and recurrence. It was open to question whether the viral genome is transcriptionally silent or active during latency. Transcription could be latency associated and thus be part of the latency phenotype. Alternatively, transcriptional activity could reflect episodes of reactivation. We demonstrate here that transcription of the immediate-early (IE) transcription unit ie1-ie3 selectiv…
Circadian rhythm in NO synthase I transcript expression and its photoperiodic regulation in the rat pineal gland.
The photoneural regulation of nitric oxide synthase type I (NOS I) expression in the rat pineal was investigated using semiquantitative RT-PCR. NOS I transcript expression exhibited a daily rhythm with peak values during the night hours. The daily rhythm in NOS I transcript expression persisted under constant dark conditions and was abolished under constant light conditions. The extent of nocturnal NOS I expression was found to be dependent on the photoperiod. It was attenuated under 20 h light and 4 h dark (L:D 20:4) compared with 12 h light and 12 h dark (L:D 12:12). The present findings indicate that, in the rat pineal, NOS I transcript expression exhibits a true circadian rhythm. Furthe…