Schwartz L M, Kay B K
Department of Zoology, Morrill Science Center, University of Massachusetts, Amherst 01003.
Dev Biol. 1988 Aug;128(2):441-52. doi: 10.1016/0012-1606(88)90306-5.
We have used immunocytological techniques to examine the developmental expression of the Ca2+-binding protein parvalbumin in Xenopus laevis embryos. Western blot experiments show that at least three different forms of parvalbumin are expressed during embryogenesis; the tadpole tail expresses one form, adult brain expresses another, mylohyoid muscle expresses both, and gastrocnemius and sartorius muscles express these two plus a third form. Parvalbumin (PV) is first detectable by immunofluorescence at stages 24-25 of development, a time when myotomal muscles are differentiating and contractile activity occurs spontaneously in embryos. At metamorphosis, PV is expressed in developing limb muscles. While the majority of skeletal muscle fibers express high levels of PV in both embryos and adults, a second fiber type has no detectable PV. The arrangement of PV-containing fibers is stereotyped in each muscle group examined. Histochemical staining of tadpole muscles indicate that PV-containing fibers correspond to fast-twitch skeletal muscles, whereas those without PV correspond to slow-twitch muscles. During tail resorption at metamorphosis, PV appears to be extruded from dying tail muscle cells and taken up by phagocytic cells.
我们运用免疫细胞技术检测了非洲爪蟾胚胎中钙离子结合蛋白小白蛋白的发育表达情况。蛋白质印迹实验表明，在胚胎发育过程中至少表达三种不同形式的小白蛋白；蝌蚪尾巴表达一种形式，成体脑表达另一种形式，下颌舌骨肌表达两种形式，而腓肠肌和缝匠肌则表达这两种形式外加第三种形式。在发育的第24 - 25阶段，通过免疫荧光首次检测到小白蛋白（PV），此时体节肌正在分化，胚胎中自发出现收缩活动。在变态期，PV在发育中的肢体肌肉中表达。虽然大多数骨骼肌纤维在胚胎和成年期都表达高水平的PV，但第二种纤维类型未检测到PV。在所检查的每个肌肉组中，含PV纤维的排列都是固定的。蝌蚪肌肉的组织化学染色表明，含PV纤维对应于快肌纤维，而不含PV的纤维对应于慢肌纤维。在变态期尾巴吸收过程中，PV似乎从垂死的尾巴肌肉细胞中挤出并被吞噬细胞摄取。
