Talmadge R J, Grossman E J, Roy R R
Department of Physiological Science, University of California, Los Angeles 90095-1527, USA.
J Exp Zool. 1996 Aug 15;275(6):413-20. doi: 10.1002/(SICI)1097-010X(19960815)275:6<413::AID-JEZ3>3.0.CO;2-R.
The myosin heavy chain (MHC) compositions of adult feline limb and diaphragm muscles were determined. Sodium dodecyl sulfate-polyacrylamide gels (SDS-PAGE) were able to separate three different MHC isoforms. This was in contrast to rat muscles, in which four MHC isoforms were separated by SDS-PAGE. The fastest migrating cat MHC migrated similar to rat type I MHC and labeled in Western blots with a monoclonal antibody (mAb) specific for slow MHC and was categorized as type I. The other two MHC isoforms labeled in Western blots with a mAb specific for fast MHC and were categorized as type II. The slowest migrating fast isoform migrated similar to rat type IIa MHC and labeled with mAb N2.261, specific for types I and IIa; therefore, this MHC was categorized as type IIa. The intermediate migrating cat MHC did not migrate similar to either rat type IIx or type IIb and was not reactive with mAbs N2.261, 35 (specific for rat I, IIa, and IIb MHCs), or F3 (specific for rat IIb MHC). In tissue sections, type IIB fibers (based on myofibrillar ATPase histochemistry) were also unstained with mAbs N2.261 and 35. Therefore, the intermediate migrating cat MHC was categorized as type IIx. Consequently, feline limb and diaphragm muscles were composed of fibers containing type I, IIa, or IIx MHCs. The observations that type I and IIa isoforms, but not IIx, had similar electrophoretic mobilities in the cat and rat and that type IIb was absent from cat limb muscles suggest that there is greater diversity in MHC isoforms IIb and IIx compared to I and IIa in cats compared to rats.
测定了成年猫科动物肢体和膈肌的肌球蛋白重链（MHC）组成。十二烷基硫酸钠-聚丙烯酰胺凝胶（SDS-PAGE）能够分离出三种不同的MHC亚型。这与大鼠肌肉不同，在大鼠肌肉中，SDS-PAGE可分离出四种MHC亚型。迁移速度最快的猫MHC与大鼠I型MHC迁移相似，并在蛋白质免疫印迹中被一种对慢MHC特异的单克隆抗体（mAb）标记，被归类为I型。另外两种MHC亚型在蛋白质免疫印迹中被一种对快MHC特异的mAb标记，被归类为II型。迁移速度最慢的快亚型与大鼠IIa型MHC迁移相似，并用对I型和IIa型特异的mAb N2.261标记；因此，这种MHC被归类为IIa型。中间迁移的猫MHC的迁移与大鼠IIx型或IIb型均不相似，并且与mAb N2.261、35（对大鼠I、IIa和IIb MHC特异）或F3（对大鼠IIb MHC特异）无反应。在组织切片中，IIB型纤维（基于肌原纤维ATP酶组织化学）也未被mAb N2.261和35染色。因此，中间迁移的猫MHC被归类为IIx型。因此，猫科动物的肢体和膈肌由含有I型、IIa型或IIx型MHC的纤维组成。I型和IIa型亚型而非IIx型在猫和大鼠中具有相似的电泳迁移率，以及猫肢体肌肉中不存在IIb型的观察结果表明，与大鼠相比，猫的MHC亚型IIb和IIx比I和IIa具有更大的多样性。
