"DIP1" does not correspond to the "flam" locus.

"flam" appears to map outside the region controlling ZAM and Idefix mobilisation ("COM").

New annotation (CR46037) in release 6.02 of the genome annotation.

See sequence feature piRNA_cluster_flamenco.

The flam locus corresponds to a cluster of piRNA's derived from nested transposable elements which span at least 130kb proximal to DIP1.

The proportion of normally copulating males is reduced in flam mutants compared to wild type. This reduction is due to changes in male behaviour. The proportion of males that perform consecutive courtship stages is significantly lower than in wild type. The sequence and duration of some courtship stages (in particular, orientation and wing vibration) is altered in mutant flies.

Cell lines carrying the permissive flam¹ allele accumulate many nuclear virus-like particles, cytoplasmic dense particles and cisternae filled with fibrous material. Two of three such cell lines have an increased copy number of the gypsy element.

In some stocks active gypsy elements are found restricted to the Y chromosome. The presence of flam alleles tends to be associated with the confinement of active gypsy elements to the Y chromosome. This might be a result of the female-specific effect of flam on gypsy activity.

gypsy virus-like particles (VLPs) accumulate inside flam¹ follicle cells close to envelope-containing membranes.

The length of time the existence of endogenous genomic gypsy was accompanied by host-virus co-evolution is studied. Host-virus co-evolution probably led to the acquisition by flam gene of the ability to control gypsy multiplication.

The expression of gypsy encoded proteins is analysed to explore how gypsy is transmitted between generations. Assembly of gypsy particles is visualised in the follicle cells of flam females by electron microscopy, these observations provide the basis for a novel model to explain how gypsy is transmitted from generation to generation. gypsy virions appear to move through the perivitelline space during a brief developmental window and infect the oocyte, providing a mechanism to explain gypsy insertion in the next generation.

Multiplication of gypsy in the germline is under the control of flam.

gypsy can be transmitted from flam strains in which it transposes to strains devoid of functional elements by egg plasm transfer or growing "empty" larvae in the presence of homogenized pupae of the flam stock. Transposition of gypsy occurs only in the progeny of females homozygous for permissive alleles of flam, where gypsy transcripts are restricted to the somatic follicle cells in the ovaries. Infectious particles which then infect the oocyte are apparently produced in these cells.

Mature gypsy particles are produced in the context of the flam mutation, which derepresses gypsy env production.

Deletion of flam does not lead to lethality or other abnormality of the flies. The only effect is on deregulation of gypsy mobilization.

The chromosomal flam locus controls the infective properties of gypsy.

Production of the gypsy\env message and corresponding protein is strongly repressed by one copy of the non-permissive allele of flam, flam^N. A less dramatic reduction in the accumulation of other transcripts and retrotranscripts is also observed. These effects correlate with the inhibition of gypsy transposition in the progeny of these females and is likely to be responsible for this phenomenon. The effects of flam on gypsy\env expression are restricted to the somatic follicle cells that surround the maternal germline.

Females homozygous for mutant flam allele show a very high rate of gypsy mobilisation, for example 10-15% reversion of ovo^D1. gypsy transcript altered on a mutant flam background.