Synucleins comprise a family of small intracellular proteins that have rece
ntly attracted considerable attention because of their involvement in human
diseases. Mutations of alpha -synuclein has been found in several families
with hereditary early-onset Parkinson's disease and accumulation of this p
rotein in characteristic cytoplasmic inclusions is a pathohistological hall
mark of several neurodegenerative diseases that have been recently classifi
ed as 'alpha;-synucleinopathies' (reviewed in Brain Res. Bull. 50 (1999) 46
5; J. Neurosci. Res. 58 (1999) 120; Philos. Trans. R. Sec. Lend. Biol. Sci.
354 (1999) 1101; Brain Pathol. 9 (1999) 733). Aggregates of beta -synuclei
n and persyn (gamma -synuclein) also have been found in dystrophic neurites
associated with Parkinson's and other neurodegenerative diseases (Proc. Na
tl. Acad. Sci. USA 96 (1999) 13450; and our unpublished observations). More
over, persyn has been implicated in malignization of breast tumours (Cancer
Res. 57 (1997) 759; Cancer Res. 59 (1999) 742; Hum. Mel. Genet. 7 (1998) 1
417). All synucleins have, distinct, although overlapping, patterns of expr
ession in the embryonic, postnatal and adult mammalian nervous systems, sug
gesting important, although still not clear, biological functions in neuron
al developing. Chicken embryo is a unique object for developmental studies
that allows in vivo manipulations not always possible for mammalian embryos
. Studies of synucleins expression in this model system could shed light on
their functions in the developing nervous system. We cloned three chicken
synucleins from the embryonic neural cDNA libraries and studied their expre
ssion in normal chicken embryonic tissues by Northern and in situ hybridiza
tion with specific probes. Our results demonstrate that primary structures
and expression patterns of synucleins are similar in birds and mammals, sug
gesting that conserved function of synucleins is important for embryonic de
velopment of vertebrates. (C) 2000 Elsevier Science Ireland Ltd. All rights
reserved.