Identification of a Drosophila Gene With Sequence Similarity to the Predicted
Human Gene pHPS[[1]]-2
Elena H. Chartoff, Jeff J. Sekelsky, William M. Gelbart
As part of the molecular analysis of the Drosophila melanogaster gene Mothers
against dpp (Mad), we cloned genomic DNA flanking the insertion site of
P{walter}(23D) (1), a P element inserted into Mad (2). Two transcription units
near P{walter}(23D) were identified by screening a cDNA library made from
early embryonic RNA (3) and probing blots of early embryonic RNA. Germline
transformation with rescue constructs indicated that one of these
transcription units corresponds to Mad (2). From the other transcription unit,
we sequenced a representative 2.4 kb cDNA, designated C24, that lies at
position +17 on the molecular map of the Mad region, approximately 6 kb
proximal to the P{walter}(23D) insertion point (2).  We refer to the gene
represented by C24 as anon-23D.
The 2255 bp sequence of C24 contains one long open reading frame (ORF) from
base 272 to 1465 (accession \# U29170). The codon frequency in this ORF is
similar to that of other Drosophila melanogaster genes (4), and the sequence
surrounding the putative translation start is a good match to the weak
consensus for translation initiation in Drosophila (5). Conceptual translation
of this ORF predicts a polypeptide with 398 amino acid residues. A search of
protein databases using the Basic Local Alignment Search Tool (6) revealed one
sequence, pHPS[[1]]-2 (accession \# P08910; 7), with strong similarity to C24.
The Poisson probability of pHPS[[1-2]] and C24 sequences matching by chance
alone was computed to be below 10[-125].  The pHPS[[1]]-2 sequence was
predicted from the sequence of a human cDNA clone fortuitously isolated in a
screen for G-protein-linked receptors (7).  Although the function of
pHPS[[1]]-2 is unknown, it shows weak similarity to G protein-linked
receptors. C24 is 43% identical and 64% similar to pHPS[[1]]-2 over its entire
length (Figure 1). Both sequences are extremely hydrophobic and have a signal
secretion sequence and at least one region predicted to be membrane-spanning.
This work was supported by a research grant from the NIH to W.M.G.
  1  .............MSTAFLTLIAVIVCILFRILNVHSQPLKPSVWCLDAH
                       3  :3 :: :: 3  33::3     3 ::  3
  1  MNAMLETPELPAVFDGVKLAAVAAVLYVIVRCLNLKSPTAPPDLYFQDSG
 38  FLDCLYKIAPVLREPYIPPRLWGFSGHVQTVLHSIVGRVRCPWPLGERVY
         3 3   3:3    3333 :33  333:33  3    3333 3 3 3 3 :
 51  LSRFLLKSCPLLTKEYIPPLIWGKSGHIQTALYGKMGRVRSPHPYGHRKF
 88  MSLKDGSTLTYDLYQPLNEQ..EDDITVAICPGIANSSESVYIRTFVHLA
 ::: 33 3  3:33:  33 3    3333: 3333333 33  333333  3
101  ITMSDGATSTFDLFEPLAEHCVGDDITMVICPGIANHSEKQYIRTFVDYA
136  QCNGYRCAVLNHIGALRSVQVTSTRIFTYGHTEDFAAMVEHLHQKYRQSR
     3  3333333333:333  : :33  3:3333  3 : 3:333  ::  3  :
151  QKNGYRCAVLNHLGALPNIELTSPRMFTYGCTWEFGAMVNYIKKTYPLTQ
186  IVAVGFSLGGNLVTKYMGEDQKTKPNKVIGGISICQGINAVEGTKWLLNW
 :3  33333333:3   33:33  3     33:  : 3:333   3: :    : 3
201  LVVVGFSLGGNIVCKYLGETQ.ANQEKVLCCVSVCQGYSALRAQETFMQW
236  QNFRRFYLYIMTENVKSIILRHRHILLSDEVKARHNLNEREI...IAAAT
        3333 ::3 : 3:3  333 33  3  3 33    3 : ::     3 :
250  DQCRRFYNFLMADNMKKIILSHRQALFGDHVKKPQSLEDTDLSRLYTATS
283  LPELDEAYTRRVYNFPSTQELYKWSSSLFYFDTIKKPMIFINAKDDPLIP
     3  :3:   3:   : 3  3 3   3 : 3   3   3::  :33 3333:
300  LMQIDDNVMRKFHGYNSLKEYYEEESCMRYLHRIYVPLMLVNAADDPLVH
333  EDLLHPIKEYATTRQNTAYVEVAHGGHLGFYEGGFLYPNPVTWLDRTLVA
     3 33   3     3 3  :3    3333333:33    3:3   3:33:3:  :3
350  ESLLTIPKSLSEKRENVMFVLPLHGGHLGFFEGSVLFPEPLTWMDKLVVE
383  MVGSLVMMHEVGKVAP             399
 :    3  3:
400  YANAIC.QWERNKLQCSDTEQVEADLE  425
Figure 1. Sequence similarity between C24 and pHSPS[[1]]-2.
The predicted C24 sequence is aligned above that of pHSPS[[1]]-2. Solid lines
indicate identical residues; dotted lines indicate similar residues. Gaps
introduced into the sequences to maximize sequence similarity are indicated by
periods. The initial alignment was produced with the GCG program GAP (8). The
output was edited manually to reflect biochemical similarities rather than
codon similarities.
References
1. Gloor, G.B., N.A. Nassif, D.M. Johnson-Schlitz, C.R. Preston, and W.R. Engels
(1991). Science 253: 1110-1117.
2. Sekelsky, J.J., S.J. Newfeld, L.A. Raftery, E.H. Chartoff, and W.M. Gelbart
(1995). Genetics 139: 1347-1358.
3. Brown, N.H. and F.C. Kafatos (1988). J. Mol. Biol. 203: 425-437.
4. Ashburner, M. (1989). Drosophila - A Laboratory Handbook. Cold Spring Harbor
Laboratory Press, Cold Spring Harbor, NY.
5. Cavener, D.R. and S.C. Ray (1991). Nucleic Acids Research 19: 3185-3192.
6. Altschul, S.F., W. Gish, W. Miller, E.W. Meyers, and D.J. Lipman (1990). J.
Mol. Biol. 215: 403-410.
7. Rapiejko, P.J., S.T. George, and C.C. Malbon (1988). Nucleic Acids Res. 16:
8721.
8. Devereux, J., P. Haeberli, and O. Smithies (1984). Nucleic Acids Res. 12:
387-395.