Eddinger T J, Wolf J A
Department of Biology, Marquette University, Milwaukee, Wisconsin 53233.
Cell Motil Cytoskeleton. 1993;25(4):358-68. doi: 10.1002/cm.970250406.
In smooth muscle tissue, two or three isoforms of myosin heavy chain (MHC) have been reported (SM1, SM2, and/or NM). In mouse uterus tissue, four bands in the region of the MHC's can be resolved on high resolution SDS polyacrylamide gels. Western blots using smooth muscle (SM) MHC-specific and nonmuscle (NM) MHC-specific polyclonal antibodies show the upper two bands in the MHC region are SM isoforms, whereas the lower two bands are NM isoforms. One-dimensional peptide maps of these four bands show each to have a unique pattern of polypeptide fragments following alpha-chymotrypsin digestion. Developmental expression of myosin heavy chains (MHC) in mouse uterus, aorta, bladder, and stomach (6 ages, 10-150 days) was determined using tissue homogenates. In the uterus, both SM MHC's show an increase in relative content with increasing age, whereas the NM MHC's show a decrease. The mouse aorta shows a significant increase in the SM MHC's and a significant decrease in the NM MHC from day 10 to day 30, which is similar to data reported for the rat aorta. Whereas both the bladder and stomach contain relatively small amounts of NM MHC's (approximately 10% or less), these quantities do show decreases with development. The SM1:SM2 ratio for the uterus remains high (3.4 at 150 days) through development; the aorta, bladder, and stomach also start out high, but tend toward 1.0 in the 150-day animals. The presence of four MHC isoforms in the uterus with unique developmental regulation of expression is consistent with hypotheses of unique functional roles for these isoforms.
在平滑肌组织中，已报道存在两种或三种肌球蛋白重链（MHC）同工型（SM1、SM2和/或NM）。在小鼠子宫组织中，在高分辨率SDS聚丙烯酰胺凝胶上可分辨出MHC区域的四条带。使用平滑肌（SM）MHC特异性和非肌肉（NM）MHC特异性多克隆抗体进行的蛋白质印迹显示，MHC区域的上两条带是SM同工型，而下两条带是NM同工型。这四条带的一维肽图显示，在α-胰凝乳蛋白酶消化后，每条带都有独特的多肽片段模式。使用组织匀浆测定了小鼠子宫、主动脉、膀胱和胃（6个年龄段，10 - 150天）中肌球蛋白重链（MHC）的发育表达。在子宫中，两种SM MHC的相对含量均随年龄增长而增加，而NM MHC则呈下降趋势。小鼠主动脉从第10天到第30天，SM MHC显著增加，NM MHC显著下降，这与大鼠主动脉报道的数据相似。膀胱和胃中NM MHC的含量相对较少（约10%或更少），但这些含量确实随发育而减少。子宫的SM1:SM2比值在整个发育过程中保持较高水平（150天时为3.4）；主动脉、膀胱和胃的该比值也开始时较高，但在150天的动物中趋于1.0。子宫中存在四种具有独特发育表达调控的MHC同工型，这与这些同工型具有独特功能作用的假设一致。
