Worm Breeder's Gazette 9(2): 24
These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.
C. elegans core histone genes (H2A, H2B, H3, H4) are arranged in 8- 10 clusters which are not tandemly arrayed. We have analyzed clones that represent about half of the genomic histone clusters and find no H1 sequences located on any of the clones. A synthetic oligonucleotide (20-mer) probe that is complimentary to a sequence found at the 3' ends of C. elegans core histone mRNAs does not hybridize to mRNAs of a size expected for H1; nor do heterologous H1 probes from chicken or sea urchin (early stage-specific) cross- hybridize with C. elegans H1 sequences. A newly isolated H1 clone from sea urchin (L. pictus, late stage specific) cross-hybridizes with C. elegans mRNAs which may encode H1. The H1-like transcripts fractionate with poly A+ messenger RNAs, whereas C. elegans core transcripts (like histone mRNAs from most other organisms), are not polyadenylated. The heterologous H1 probe also hybridizes to two bands in a Southern blot analysis of Bristol and Bergerac genomic DNA digested with either EcoRV or BamHI. The heterologous H1 probe was used to screen a Bristol clone bank. Two different phages were isolated that contain inserts homologous to the probe. The restriction maps of the two inserts indicate that they do not contain overlapping fragments. The heterologous H1 probe hybridizes to a ~6.8 kb EcoRI fragment contained within one clone, and to two EcoRI fragments (~3.8, 3.0 kb) in the second clone. Neither phage contain core histone sequences. Experiments are in progress which will determine whether the cloned sequences which hybridize to the heterologous H1 probe are C. elegans H1 genes.