Novel Technique Shows When the Fertilized Egg’s Genome Comes into Its Own

Liza Gross

doi:10.1371/journal.pbio.0050131

Abstract

Novel Technique Shows When the Fertilized Egg’s Genome Comes into Its Own

Highlights

You might say that a mother’s influence begins even before her offspring were just a twinkle in dad’s eye
During egg cell development, the mother deposits gene products—consisting largely of messenger RNAs and some proteins—into the developing egg. These mRNAs take over after fertilization to orchestrate the earliest stages of embryogenesis
Investigators have traditionally classified increased transcripts as zygotic, stable transcripts as maternal, and down-regulated transcripts as degraded maternal transcripts. Because this interpretation doesn’t account for concomitant degradation and transcription—mRNA levels can drop or stay the same even with a zygotically active genome if maternal transcripts disappear at the same time—De Renzis et al developed an approach to distinguish the two mechanisms clearly

Summary

Introduction

You might say that a mother’s influence begins even before her offspring were just a twinkle in dad’s eye. By matching gene transcripts with their corresponding DNA template across the genome, the researchers identified classes of zygotically and maternally expressed genes and show that the embryo combines (zygotic) transcription with (maternal) message degradation to produce the localized patterns of gene expression required for organizing the early embryo. The details of zygotic genome activation have remained elusive partly because maternal transcript degradation proceeds alongside zygotic gene transcription.

Results

Conclusion