The Journal of Cell Biology, Vol 81, 403-410, Copyright © 1979 by The Rockefeller University Press
Spermatogenesis in the mouse. I. Autoradiographic studies of nuclear incorporation and loss of 3H-amino acids
JF Mayer Jr and BR Zirkin
Autoradiographic and electron microscope methods were used to correlate
changes in nucleoproteins with nuclear fine structure during
spermatogenesis in the mouse. Testes were fixed at daily intervals after
intratesticular injectionwith labeled amino acid. [3H]Arginine, lysine,
valine, and proline were rapidly incorporated into primary spermatocyte
nuclei, retained through subsequent spermatocyte divisions and through
spermatid differentiation to step 12 of spermiogenesis, but were lost with
spermatid differentiation beyond step 12. Arginine and lysine (not valine
or proline) also were rapidly incorporated into certain elongated spermatid
nuclei but differed strikingly in their distribution and fate. Nuclei of
late step-12 through step-15 spermatids were initially labeled with
arginine. This label was retained through subsequent spermatid
differentiation and sperm maturation in the epididymis. By contrast, lysine
was initially incorporated only into late step-12 and step-13 spermatid
nuclei, and was retained only to early step 14 of spermiogenesis. Spermatid
incorporation of lysine coincided with the initiation of chromatin
condensation in late step-12 nuclei, and loss of lysine coincided with the
completion of condensation in step-14 nuclei.
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati What's this?
