Alignment of RT1-E2 protein sequences deduced from the cDNA sequences summarised in Table 1 with those of other rat class I sequences. For E2ba (acc. AJ537439), the translated sequence ends prematurely because of a frameshift at the start of exon 5 (see text). The line E2ba* shows the notional downstream translation of the cDNA sequence if this frameshift was not present. In the sequences from which the RT1-E2g (acc. AJ243338) sequence was compiled (p57, p4.4, p4.6), underlined residues correspond to positions that differ from all the other RT1-E2 sequences, and could therefore be due to either PCR mutations or true allelic differences. Others accession numbers are as follows: E2bu: AJ537420, E2bl: AJ537417, E2an (deduced from genomic): AJ315490, E2al: AJ276126, E2cl: AJ537418, E2dl: AJ537419, E2dc: AJ537441, Eav1: AJ537440, Eu: AJ306619, Al: L26224, Aa: M31018, Au: X82106. Alignment of the corresponding DNA sequences is available as supplementary data or upon request email@example.com.