EMBO Fellows Meeting 2012

Saskia Houwing
EMBO Fellows Meeting 2012
Activation of the germline transcriptional program in Drosophila
Abstract
In order to maintain the totipotency of germ cells and prevent differentiation, transcription of somatic genes
must be repressed while transcription of germ genes must be activated. Repressors of RNA polymerase II (RNA
pol II) transcription have been well described such as the maternally provided factor, polar granule component
(pgc). However, it is unknown which proteins directly activate transcription in the germ cells after the inhibition
of RNA pol II is lifted immediately following gastrulation. Neither genetic nor molecular screens have yet
identified any maternal factors that encode for transcriptional regulators involved in germline-specific gene
expression. Similarly, very few genes have been identified which are transcribed in germ cells at these earliest
stages.
Germ cells isolated from different stages of early Drosophila embryos were used to identify all transcripts by
RNA-seq that are maternally provided and localize to germ cells, as well as transcripts that are expressed at
the onset of zygotic transcription in the germline. Analysis of expression levels reveals 94 genes that are
zygotically transcribed as early as embryonic stage 8-9, and 121 genes that are transcribed by stage 12-13, in
Drosophila germ cells. These genes were used to search for transcription factor binding motifs in order to
identify the transcriptional regulatory pathways that help specify germ cells. In addition, small RNA sequence
information, as well as expression levels of long non-coding RNAs and transposons are helping us gain a
complete picture of the processes that regulate germline gene expression.
Skirball Institute, NYU School of Medicine, 540 First Avenue, New York, NY 10016, USA
14-17 June 2012, Heidelberg, Germany