Worm Breeder's Gazette 10(3): 79
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.
While determining the 5' ends of C. elegans GAPDH mRNAs by primer extension sequencing, we found a new trans-spliced leader (SL2). The previously identified SL is present on mRNAs from three of the four C. elegans GAPDH genes. However, a new 22-nucleotide spliced leader sequence is found on mRNA from one of the four GAPDH genes. RNA Northern analysis showed that the SL2 is present on many RNAs isolated from C. elegans var. Bristol, C. elegans var. Bergerac and C. briggsae, but not on RNAs from Panagrellus redivivus and Haemonchus contortus. In this regard it differs from the original SL that is found in other nematodes. The hybridized RNAs showed a broad spectrum of different molecular weights. From the genomic Southern blot, it seems there are two clusters of SL2 genes. We have screened a C. elegans EMBL4 genomic library. Two groups of phages were isolated. Using the phage DNAs as templates, two kinds of SL2 genes have been sequenced. These two genes are nearly identical in the SL RNA region but differ in the 5' and 3' flanking regions. A consensus Sm binding site of snRNAs is present. The SL2 RNA can be folded into a secondary structure similar to that proposed for the original SL RNA. The SL2 RNA probably has a TMG cap because it can be precipitated by anti-TMG-antibody. The original SL and the new SL2 are similar; 16 out of 22 nucleotides are the same in the best alignment.