Antibody:	anti-nucleolin polyclonal antibody
Detection system:	Secondary antibody coupled to colloidal gold

Structure	Level	Pattern	Image	Note
TS1: 1-cell stage embryo	Present	Regionally restricted	2	The prenucleolar masses were labelled with the anti-nucleolin antibody. The gold grains are regularly scattered on the compact nucleolus. The nucleoplasm is not significantly labelled.

Structure	Level	Pattern	Image	Note
TS2: 2-cell stage embryo	Present	Regionally restricted	4	The labelling density over the compact fibrillar mass remains similar to that of the zygote.

Structure	Level	Pattern	Image	Note
TS3: 4-8 cell stage embryo	Present	Regionally restricted		The gold grains are present on the still condensed area as well as on the nucleolonemal network. The labelling pattern and density are comparable to that for B23.

Structure	Level	Pattern	Image	Note
TS4: compacted morula	Present	Regionally restricted	7	B23 and nucleolin co-localize on dense fibrillar components and granular components. The residual condensed core masses are virtually unlabelled.

Structure	Level	Pattern	Image	Note
TS4: blastocyst	Strong	Regionally restricted	9	The nucleolus displays no more condensed areas and is heavily labelled with both B23 and nucleolin. They co-localize on the dense fibrillar components and the granular components, the fibrillar centers being devoid of labelling.