Table 1.

Occurrence and proposed functions of DDX6-like RNA helicases

Organism	Protein	Expression	Location	Function
Xenopus laevis	Xp54	Oocytes and early embryos	Maternal mRNP particles	mRNP assembly
				Translation regulation
			Balbiani body	Required for progression of meiosis
Mouse	p54	Gametes and early embryos	Maternal mRNP particles	Translation regulation
Drosophila melanogaster	Me31B	Oocytes and early embryos	Maternal mRNP particles	Translation repression
			Sponge body
Caenorhabditis elegans	CGH-1	Germ cells and early embryos	mRNP particles P granules	Modulation of physiological germ cell apoptosis
Spisula solidissima	p47	Oocytes and early embryos	Maternal mRNP particles	Translation repression
S.pombe	Ste13p			Essential for progression of meiosis
S.cerevisiae	Dhh1p		mRNP particles	Required for sporulation
			P bodies	Translation repression
				mRNA degradation
				G1/S checkpoint control
Mammals	Rck/p54	Somatic cells	P bodies	mRNA degradation
			SGs	mRNP remodelling
Mammals	Rck/p54	Over-expression in tumour cells	Cytoplasmic particles	Candidate proto-oncogene
				Translation regulation

See text for references.