Heterochromatin protein 1a (HP1a) is a highly conserved and versatile epigenetic 
factor that can both silence and activate transcription. However, the function 
of HP1a in development has been underinvestigated. Here, we report the role of 
maternal HP1a in producing maternal transcripts that drive early Drosophila 
embryogenesis. Maternal HP1a upregulates genes involved in translation, mRNA 
splicing, and cell division, but downregulates genes involved in neurogenesis, 
organogenesis, and germline development, which all occur later in development. 
Our study reveals the earliest contribution of HP1a during oogenesis in 
regulating the production of maternal transcripts that drive early Drosophila 
embryogenesis.