The transposon A(R)4-24P[white, rosy] in Drosophila melanogaster is subject to position-effect variegation at a non-centromeric insertion site.
The white gene within the transposon A(R)4-24P[white,rosy] inserted at cytological location 24D1-2 in the euchromatic portion of the Drosophila melanogaster genome exhibits a mosaic pattern of expression which is modified by temperature and Y-chromosome number, as in cases of classical position-effect variegation (PEV). The eye colour of the flies in this variegated stock remains mosaic in the presence of the PEV modifier Su(var)3-6, slightly less so with Su(var)3-9 and Su(var)2-5, and full suppression of variegation occurs in the presence of Su(var)3-7. We have induced further transposition of A(R)4-24 and isolated two mosaic stocks with this transgene at new cytological locations. In these stocks, the A(R)4-24 transposon was flanked by the same genomic DNA fragments as in the original location. Spontaneous loss of these fragments leads to reversion of the variegated eye colour to wild-type. We suggest that the flanking DNA fragments from 24D1-2 are capable of inducing position-effect variegation without any association with centromeric heterochromatin. In situ hybridisation and Southern analysis demonstrate that the 5' flanking genomic fragment contains repeated sequences which are abundantly present in heterochromatin.
Balasov
M L
ML
Institute of Cytology and Genetics of the Siberian Division of the Russian Academy of Sciences, Novosibirsk. max@bionet.nsc.ru
Belyaeva
E S
ES
Shestopal
S A
SA
Makunin
I V
IV
Zhimulev
I F
IF
D018528:ATP-Binding Cassette Transporters; D000818:Animals; D002503:Centromere / Q000235:genetics*; D003001:Cloning, Molecular; D003433:Crosses, Genetic; D004251:DNA Transposable Elements; D015245:Deoxyribonuclease BamHI / Q000235:genetics / Q000378:metabolism; D015247:Deoxyribonuclease HindIII / Q000235:genetics / Q000378:metabolism; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000235:genetics*; D005136:Eye Proteins / Q000235:genetics; D005260:Female; D006570:Heterochromatin / Q000235:genetics; D019476:Insect Proteins / Q000235:genetics; D008297:Male; D009030:Mosaicism; D009799:Ocular Physiological Phenomena; D012097:Repressor Proteins / Q000235:genetics; D017422:Sequence Analysis, DNA
D018528:ATP-Binding Cassette Transporters; D004251:DNA Transposable Elements; D029721:Drosophila Proteins; D005136:Eye Proteins; D006570:Heterochromatin; D019476:Insect Proteins; D012097:Repressor Proteins; C089148:Su(var)3-9 protein, Drosophila; C059254:w protein, Drosophila; D015245:Deoxyribonuclease BamHI; D015247:Deoxyribonuclease HindIII