Submitted to: American Society of Plant Biologists Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 8/3/2002
Publication Date: 8/7/2002
Citation: Velten, J.P., Oliver, M.J. 2002. Replacement histones: a role in desiccation tolerance in moss[abstract]? American Society of Plant Biologists, August 3-7, 2002, Denver, Colorado. CDROM.
Technical Abstract: Analysis of an expressed sequence tag (EST) cDNA library from the desiccation-tolerant moss, Tortula ruralis, identified a clone, RNP49, with strong sequence similarity to genes encoding histone, H3, a component of the core nucleosome in all eukaryotes. The RNP49 cDNA clone was produced using mRNA contained within messenger RNA protein (mRNP) particles that are sequestered during drying and contain mRNA for "rehydrin" genes associated with desiccation recovery (Wood, Duff & Oliver, 1999). H3 histone genes are grouped into two broad classes based primarily upon expression characteristics. The 'cell cycle dependent' H3 genes are transcribed only in actively dividing cells during the S phase of the cell cycle, providing histones for association with newly synthesized DNA. A second class of H3 genes, those encoding 'replacement' histones, are characterized by expression outside the S phase and are thought to provide new histones to replace those lost to turnover. We have recently determined that the RNP49 cDNA appears to represent the product of a replacement H3 gene in T. ruralis. A reasonable hypothesis is that existing histone proteins in Tortula are likely to be adversely effected by desiccation and that the RNP49 gene may contribute to desiccation tolerance through replacement of damaged His3 during recovery. Such a scenerio provides a potential mechanism for regulation of post-desiccation gene regulation via chromatin remodeling and alterations in covalent histone modifications.