The rotavirus outer capsid proteins VP4 and VP7 determine the P- and G
-serotypes, respectively, of the virus. Three types of VP4 protein are
commonly found in human rotaviruses (P4, P6 and P8) which are encoded
by distinct VP4 gene alleles. We developed a non-radioactive Northern
hybridization method for the P-genotyping of rotavirus field isolates
. Double-stranded RNA was isolated from faecal specimens of rotavirus
positive patients. Digoxigenin (DIG)-labelled cDNA probes derived from
the VP4 gene of the standard strains RV5 (P4), ST3 (P6) and RV4 (P8)
were used to discriminate between the different alleles. Although the
P4 probe exhibited cross-reactivity with some P8 samples, the P6 and P
8 probes were found to be type-specific. In addition, the probes did n
ot react with standard strains representative of other defined human a
nd animal rotavirus P-types. Use of these probes on viral RNA of faeca
l origin allowed approximately 70% of samples to be assigned a P-type.
This method complements PCR- and EIA-based P-typing methods, is relat
ively inexpensive and is readily applicable to large numbers of sample
s, thus proving useful for epidemiological studies.