Menin controls the concentration of retinoblastoma protein.

Menin, the protein encoded by the Multiple Endocrine Neoplasia type 1 gene, is involved in the cell cycle control through its participation in functional dynamics of chromatin and regulation of transcription. RB, the protein of the retinoblastoma gene RB1, controls the progression of the cell cycle and is regulated in its activity by means of a feedback by phosphorylation. Studies in double heterozygous knockout mice for Men1 and the Retinoblastoma gene Rb1 have recently indicated that both genes may be implicated in the same pathways.

The bacterial Tn9 chloramphenicol resistance gene: an attractive DNA segment for Mos1 mariner insertions.

The eukaryotic mariner transposons are currently thought to have no sequence specificity for integration other than to insert within a TA contained in a degenerated [TA](1-4) tract, either in vitro or in vivo. We have investigated the properties of a suspected hotspot for the integration of the mariner Mos1 element, namely the Tn9 cat gene that encodes a chloramphenicol acetyl transferase. Using in vitro and bacterial transposition assays, we confirmed that the cat gene is a preferential target for MOS1 integration, whatever its sequence environment, copy number or chromosomal locus.