ovo, a Drosophila gene required for ovarian development, is specifically expressed in the germline and shares most of its coding sequences with shavenbaby, a gene involved in embryo patterning

Abstract

Genetic analyses of Drosophila oogenesis have revealed the central role of ovo, a gene required for differentiation of the female germline. A number of recessive ovo mutations also affect the shavenbaby (svb) function required for late embryo patterning, suggesting a tight structural link between ovo and svb. By using various genomic probes for in situ hybridization to wild type and mutant embryos, we show that ovo indeed shares most of its coding sequences with svb. svb expression is detected early in the presumptive head region and later in each segment. It requires control elements located upstream of the ovo genomic region. ovo expresses abundant maternal RNAs which are uniformly distributed in early cleavage embryos. A fraction that lacks an alternative ovo-specific protein coding region (ORF 2b) is detected in pole cells. Expression of an ovo-specific lacZ reporter gene (ovoB) shows that ovo encodes a nuclear protein present in the germline of both sexes. Zygotic ovoB expression is first detected in embryos at around stage 17 and persists up to the adult stage. Our data show that the germline specific expression of ovo in females correlates with its function in oogenesis. This expression, however, is also observed in males in which ovo is not required.

Ovol2, a Mammalian Homolog of Drosophila ovo: Gene Structure, Chromosomal Mapping, and Aberrant Expression in Blind-Sterile Mice

“…2B), with sizes expected for Ovol2A transcripts. This result suggests that Ovol2B transcription initiates from an internal promoter, and the Ovol2A and Ovol2B isoforms are produced as a result of alternative promoter usage and alternative splicing, much like the multiple Drosophila ovo transcripts [9][10][11].…”

“…Drosophila ovo, being the prototype of ovo genes, is the most extensively characterized. It is a complex locus encoding multiple transcripts generated by alternative promoter usage and alternative splicing [10,11]. These transcripts encode multiple protein isoforms, all containing four identical Cys2/His2 zinc fingers at their carboxy termini but different amino-terminal domains.…”

The structure and evolution ofcis-regulatory regions: theshavenbabystory

“…The shavenbaby mRNA is one of three mRNAs produced by the ovo locus [10,11]. The other two mRNAs, ovoA and ovoB, are expressed only in the germline and are required for proper ovary development [10,11]. Svb is expressed in the epidermis of the embryo (figure 2a), and this expression is sufficient to induce cell-autonomous development of trichomes [12].…”

“…At this point in the story, it is worth taking a brief interlude to explain what is known about svb function, much of which has been revealed by the efforts of the laboratory of François Payre and Serge Plaza. The shavenbaby mRNA is one of three mRNAs produced by the ovo locus [10,11]. The other two mRNAs, ovoA and ovoB, are expressed only in the germline and are required for proper ovary development [10,11].…”

Conserved regulatory architecture underlies parallel genetic changes and convergent phenotypic evolution

“…In Drosophila larvae, differentiation of cells with trichomes, as opposed to smooth cuticle, is controlled by the transcription factor Shavenbaby (svb) (19), whose activity is both necessary and sufficient to produce trichomes (20). The complex embryonic expression pattern of svb in D. melanogaster is determined by the activity of seven enhancers that are distributed throughout a region ∼90 kb upstream of the svb first exon (17,18) (Fig.…”