Macrotubules have been described1 in cells infected
with Umatilla virus (UMAV), an orbivirus for which bluetongue virus (BTV) is
the protype. Macrotubules, often in linear array, were observed in the
cytoplasm and in intimate association with viroplasms of infected cells.
Macrotubules had outside and inside diameters of 20 and 15 nm and many had
dark-staining centers with diameters similar to the interiors of the
tubules. UMAV was 60 nm and the RNA core was 30 nm in diameter. This report
describes the association of UMAV with macrotubules and two types of
microtubules.
