Cst. Pow et Ag. Hendrickx, LOCALIZATION OF INTEGRIN SUBUNITS ALPHA-6 AND BETA-1 DURING SOMITOGENESIS IN THE LONG-TAILED MACAQUE (MACACA-FASCICULARIS), Cell and tissue research, 281(1), 1995, pp. 101-108
The distribution of integrin subunits alpha 6 and beta 1, and the alph
a 6 beta 1 integrin ligand, laminin, was examined during somitogenesis
in developmental stages 11, 13, and 16 in the long-tailed macaque, us
ing peroxidase immunocytochemistry. Within differentiating somites in
stage 11, alpha 6 expression was observed in the sclerotome, basal sur
face of dermamyotomal cells adjacent to the basal lamina and on scatte
red cells throughout the dermamyotome. In further advanced somites in
stages 13 and 16, alpha 6 immunoreactivity became restricted to the my
otome. alpha 6 was expressed on mesenchymal core cells within the myoc
ele of undifferentiated epithelioid somites and the ventromedial wall
of somites commencing differentiation at each stage. beta 1 distributi
on resembled that of alpha 6 in stage 11 semitic tissue, however, it r
emained present on myotome and sclerotome cells in the later stages, a
nd was also expressed on dermatomal cells in stage 16. Laminin immunor
eactivity, while more intense and prevalent than alpha 6 and beta 1 in
each stage examined, occurred on the same somite cell populations as
the 2 integrin subunits. These results show a defined distribution of
alpha 6 on semitic tissue, and suggest this integrin is involved in so
mite differentiation. They also support a possible role for alpha 6 in
myoblast formation and migration. Overlapping of beta 1 and laminin i
mmunoreactivity with that of alpha 6 further suggests that alpha 6 pai
rs with beta 1 as a functional heterodimer for laminin in defined semi
tic regions.