Epigenetic regulation of an IAP retrotransposon in the aging mouse: progressive demethylation and de-silencing of the element by its repetitive induction.

The recent insertion of a murine intracisternal A-particle (IAP) retrotransposon within one of the introns of a housekeeping gene, the circadian m.nocturnin gene, revealed a singular expression profile, both throughout the daytime and the mouse life span. Measurement of the levels of transcripts from this element by quantitative real-time RT-PCR, in organs of 1-24-month-old mice, disclosed that the inserted element--which is part of a large family of otherwise severely repressed mobile elements--becomes active upon aging, specifically in the liver where the m.

A murine gene with circadian expression revealed by transposon insertion: self-sustained rhythmicity in the liver and the photoreceptors.

We have previously identified in some mouse strains (e.g. BALB/c, DBA/2) a murine Intracisternal A-particle (IAP) transposable element specifically expressed in the liver.

Identification of four families of yCCR4- and Mg2+-dependent endonuclease-related proteins in higher eukaryotes, and characterization of orthologs of yCCR4 with a conserved leucine-rich repeat essential for hCAF1/hPOP2 binding.

Background: The yeast yCCR4 factor belongs to the CCR4-NOT transcriptional regulatory complex, in which it interacts, through its leucine-rich repeat (LRR) motif with yPOP2. Recently, yCCR4 was shown to be a component of the major cytoplasmic mRNA deadenylase complex, and to contain a fold related to the Mg2+-dependent endonuclease core.

Results: Here, we report the identification of nineteen yCCR4-related proteins in eukaryotes (including yeast, plants and animals), which all contain the yCCR4 endonuclease-like fold, with highly conserved CCR4-specific residues.

Characterization of a mammalian gene related to the yeast CCR4 general transcription factor and revealed by transposon insertion.

Murine intracisternal A-particles (IAPs) are reiterated retrovirus-like transposable elements that can act as insertional mutagens. Accordingly, we previously identified a chimeric transcript initiated at an IAP promoter and extending through a 3'-located open reading frame with significant similarity to the C-terminal domain of the yeast CCR4 general transcription factor. In this report, we characterize the corresponding murine gene, mCCR4, and its human homologue, thus providing the first description of CCR4-like factors in mammals.