CLONING AND CHROMOSOMAL LOCALIZATION OF A CDNA-ENCODING A MITOCHONDRIAL PORIN FROM DROSOPHILA-MELANOGASTER

We have raised polyclonal antibodies against purified the Drosphila me lanogaster mitochondrial porin, They showed high titre and specificity and were thus used as a tool for screening an expression library, The isolated clone 1T1 showed 74% sequence identity in the last 19 residu es at the C-terminus of human porin, A subclone of 1T1, containing the porin-like sequence, was thus used as a probe for re-screening a cDNA library and several positive clones were plaque-purified, We present here the sequence of a 1363 bp cDNA encoding a protein of 279 amino ac ids. Its identity with porin was also confirmed by N-terminal Edm;an d egradation of the purified protein, The D. melanogaster porin shows an overall 51.8% identity with human porin isoform 1 (porin 31HL or HVDA C1) and an overall 55.7% identity with human porin isoform 2 (HVDAC2), Hydrophobicity plots and secondary structure predictions showed a ver y high similarity with data obtained from known porin sequences, The D I. melanogaster porin cDNA was used as a probe for in situ hybridizati on to polytenic salivar gland chromosomes, It hybridizes with differen t intensities in two sites, in chromosome 2L, at region 31E and in chr omosome 3L at region 79D, Thus, also in Drosophila melanogaster porin polypeptide(s) belong(s) to a multigene family.