msl2 mRNA is bound by free nuclear MSL complex in Drosophila melanogaster
In Drosophila, the global increase in transcription from the male X chromosome to compensate for its monosomy is mediated by the male specific lethal (MSL) complex consisting of five proteins and two non coding RNAs, roX1 and roX2. After an initial sequence dependent recognition by the MSL complex of 150 300 high affinity sites, the spread to the majority of the X linked genes depends on local MSL complex concentration and active transcription. We have explored whether any additional RNA species are associated with the MSL complex. No additional roX RNA species were found, but a strong association was found between a spliced and poly adenylated msl2 RNA and the MSL complex. Based on our results, we propose a model in which a non chromatin associated partial or complete MSL complex titrates newly transcribed msl2 mRNA and thus regulates the amount of available MSL complex by feedback. This represents a novel mechanism in chromatin structure regulation.
Nucleic acids research