Table 2. List of PCR primers.

Primer Name	primer sequence	Expected fragment size (bp)	Annealing temp. (C°)
p1F	F: CACCCTTCATGAGGATGAGC	677, 955	61
p3/5F	F: CCGCAGGTCTCTTGGAAAC	513, 669	63
p4F	F: TGGACCAAAGACAGAGGAGAATC	606, 762	63
p9R	R: CCTGCTGCTCTGCGCTTAC
hACTB	F: ATGCAGAAGGAGATCACTGC	508	55
	R: GTCCTCGGCCACATTGTGAA

To detect and clone all potential human MRO splice variants, primer pairs were designed based on sequences retrieved from electronic gene databases (NM_031939.3, NM_001127174.1, NM_001127175.1, NM_001127176.1). Specific primer pair combinations (F: Forward primer, R-reverse primer) were used to characterize potential splice variants. Primers p1-Forward (p1F) together with p9-Reverse (p9-R) enabled us to clone the 'MROb' isoforms containing the distal 5’UTR, while primer p3/5-F spanning exons 3/5, skipping exon 4, together with p9-R facilitated the cloning of MROa, MROc and MROd containing the proximal 5’UTR. Primer p4-Forward (p4F) together with p9-R enable the cloning of the coding region. hACTB—Human beta-actin.