Ae. Duggan et Ip. Callard, Phylogenetic distribution of apolipoproteins A-I and E in vertebrates as determined by western blot analysis, J EXP ZOOL, 290(3), 2001, pp. 255-264
A putative apolipoprotein E (apoE) has been identified in the HDL and VHDL
fractions of the turtle. This observation is of particular interest conside
ring apoE has been reported absent in the domestic hen (Hermier et al., '95
; Biochim Biophys Acta: 105-118, 1995) and thus presumed absent in nonmamma
lian vertebrates altogether. As a result, partial amino acid sequencing of
this protein was performed and revealed that one fragment shared 41% sequen
ce identity to human apoE. Western blot analysis using antisera to apoE dem
onstrated cross-reactivity to a 34-kDa protein (putative apoE) in turtle pl
asma. Further investigation using anti-apoE antibody in Western blot analys
is detected immunoreactive apoE in the plasma of lamprey, spiny dogfish, sk
ate, and alligator, but not in flounder, newt or python; its absence in sev
eral species of birds was confirmed. Using anti-apoA-I antibody, apoA-I was
detected in all vertebrate groups except a representative teleost (flounde
r). Apo-A-I antibody cross-reacted weakly with some putative apoE proteins
(chicken, spiny dogfish and skate) and the reverse was true for anti-apoE,
which cross-reacted with putative apoA-I in birds, reptiles, and elasmobran
chs, confirming the molecular similarity and phylogenetic relatedness of th
ese two proteins. (C) 2001 Wiley-Liss, Inc.