Worm Breeder's Gazette 15(1): 43 (October 1, 1997)
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.
|2||MGH Cancer Center, Charlestown, MA and Department of Pathology, Harvard Medical School, Boston, MA|
Neuropeptides form the largest class of neuroactive substances, yet as a group their roles in nervous system function and development are still poorly understood. Only the FMRFamides and related neuropeptides (FaRPs) have been intensely studied in C. elegans. However, in Aplysia californica, over 40 neuropeptides have been identified and characterized. This suggests that many C. elegans neuropeptides have not yet been discovered. With the near completion of the C. elegans genome sequencing project, reverse genetic techniques can be applied to identify C. elegans neuropeptide genes. We are using FASTA and BLAST to search with previously identified neuropeptide sequences (stored in GENBANK) against the C. elegans genome sequence. We expect the products of neuropeptide genes to fit a prepropeptide model: they should contain a putative signal peptide region, followed by interrupted multiple repeats of the same or similar neuropeptide. Additionally, the predicted neuropeptides should be flanked by pairs of basic amino acids (KR, RR, KK, RK) or less frequently by monobasic residues (R or K) which are preferred sites of endoproteolytic cleavage. Potential C. elegans neuropeptide gene compatible with the prepropeptide model are then selected for molecular and genetic analysis. We are currently analyzing C. elegans genes encoding neuropeptides similar to Aplysia buccalin (C. elegans C01C4.1) and myomodulin (C. elegans T24D8.3, T24D8.4, T24D8.5 and T01B6.4). (See below.) Even though the predicted C. elegans neuropeptide sequences are not strikingly similar to the Aplysia neuropeptides, there is strong internal homology between neuropeptides within the same C. elegans genes. We are creating reporter constructs by fusing the promoter region of potential neuropeptide genes to the GFP gene using Fire laboratory vectors. We are injecting these reporter constructs to assess cellular expression patterns of these myomodulin-like and buccalin-like genes. We think that it is likely that the GENEFINDER predicted genes of T24D8.3, .4 and .5 are exons of a single gene. We will use RT-PCR to determine mRNA splicing patterns. Our long range goals include creating mutations in these genes and determining the function of these and other putative C. elegans neuropeptides. Identity is indicated with a colon, gaps with underlining. SLSMLRLG____ Aplysia Myomodulin A :MA:G:::LRPG T24D8.5 :MAYG:Q:FRPG # :IALG:S:FRPG :MAIG:A:MRPG T24D8.4 :IAIG:A:FRPG T24D8.3 N:LVG:Y:FRIG T01B6.4 DPNVDPYSYLPSVG Aplysia Buccalin _VNL::N:FRM:F: C01C4.1 ___M:ANAFRM:F: # ___M::NAFRM:F: # 3 identical neuropeptides of this sequence are encoded by this gene.