Translational control of maternal Cyclin B mRNA by Nanos in the Drosophila germline

Development. 2007 Apr;134(8):1519-27. doi: 10.1242/dev.002212. Epub 2007 Mar 14.

Abstract

In the Drosophila embryo, Nanos and Pumilio collaborate to repress the translation of hunchback mRNA in the somatic cytoplasm. Both proteins are also required for repression of maternal Cyclin B mRNA in the germline; it has not been clear whether they act directly on Cyclin B mRNA, and if so, whether regulation in the presumptive somatic and germline cytoplasm proceeds by similar or fundamentally different mechanisms. In this report, we show that Pumilio and Nanos bind to an element in the 3' UTR to repress Cyclin B mRNA. Regulation of Cyclin B and hunchback differ in two significant respects. First, Pumilio is dispensable for repression of Cyclin B (but not hunchback) if Nanos is tethered via an exogenous RNA-binding domain. Nanos probably acts, at least in part, by recruiting the CCR4-Pop2-NOT deadenylase complex, interacting directly with the NOT4 subunit. Second, although Nanos is the sole spatially limiting factor for regulation of hunchback, regulation of Cyclin B requires another Oskar-dependent factor in addition to Nanos. Ectopic repression of Cyclin B in the presumptive somatic cytoplasm causes lethal nuclear division defects. We suggest that a requirement for two spatially restricted factors is a mechanism for ensuring that Cyclin B regulation is strictly limited to the germline.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • 3' Untranslated Regions
  • Animals
  • Base Sequence
  • Cyclin B / biosynthesis*
  • Cytoplasm / metabolism
  • DNA-Binding Proteins / metabolism
  • Drosophila / embryology
  • Drosophila / metabolism*
  • Drosophila Proteins / metabolism
  • Drosophila Proteins / physiology*
  • Gene Expression Regulation, Developmental
  • Molecular Sequence Data
  • Oocytes / metabolism*
  • Protein Binding
  • Protein Biosynthesis
  • RNA, Messenger / biosynthesis*
  • RNA-Binding Proteins / metabolism
  • RNA-Binding Proteins / physiology*
  • Ribonucleases / metabolism
  • Transcription Factors / metabolism

Substances

  • 3' Untranslated Regions
  • Cyclin B
  • DNA-Binding Proteins
  • Drosophila Proteins
  • RNA, Messenger
  • RNA-Binding Proteins
  • Transcription Factors
  • hb protein, Drosophila
  • pum protein, Drosophila
  • nos protein, Drosophila
  • CCR4 protein, Drosophila
  • Ribonucleases