We have isolated two DNA elements-Eh MRS1 and Eh MRS2-from Entamoeba histolytica, which contain the eukaryotic consensus Scaffold/Matrix Attachment Region (S/MAR) bipartite recognition sequences. Both these sequences bind to high salt extractable nuclear proteins and insoluble nuclear matrix proteins in E. histolytica HM1:IMSS, suggesting that the predicted S/MAR recognition sequences may indeed function as scaffold attachment regions in E. histolytica. Sequence analysis shows that Eh MRS1 and Eh MRS2 contain internal tandem repeats ranging from units of 8-11bp and are themselves present as independent arrays of tandemly repeating units of approximately 1100bp each. Eh MRS1 and Eh MRS2 are localised on different chromosomes in E. histolytica HM1:IMSS. Both Eh MRS1 and Eh MRS2 also code for small molecular weight RNAs of unknown function. Thus, two unique sequences-Eh MRS1 and Eh MRS2-demonstrate very similar properties, suggesting that they belong to a superfamily of genomic elements, which may function as scaffold or matrix attachment sites in Entamoeba.
Bibliographical noteFunding Information:
We are thankful to TIGR, USA and Wellcome Sanger Centre, UK for releasing the E. histolytica sequences in the public database before the completion of the projects. This study was supported by grants from CSIR (Grant number—37 (0983)/98/EMR-II) and DBT (BT/PR1220/Med/09/198c/98), Government of India to A.L.
- Clustered repeats
- Nuclear matrix proteins
- Repetitive DNA
- Scaffold or matrix attachment regions
- Small molecular weight RNA