Mutant/mutation
The mutant lacks expression of serine repeat antigen 1(SERA1; cysteine protease, putative) and lacks expression of serine repeat antigen 2 (SERA2; papain family cysteine protease, putative).

Protein (function)
Plasmodium species possesses SERAs of two major groups, specified as 'cysteine-type SERAs' and 'serine-type SERAs'. Serine-type SERAs contain an active site serine residue instead of the canonical cysteine residue. The genomes of different Plasmodium species contain different numbers of SERA genes. P. falciparum possesses nine SERA protease genes whereas the P. berghei genome contains five. P. falciparum possesses six “serine-type” (SERA1 to SERA5 and SERA9) and three “cysteine-type” (SERA6 to SERA8) SERAs. In P. falciparum mutants have been generated lacking expression of SERA1, 2, 3, 4 , 7, 8 and 9 without a distinct phenotype in the blood stages (MvCoubrie J.E. et al,  2007, Infection and Immunity, 75:5565-74).

SERA genes of P. berghei are arranged in a tandem cluster that contains two serine-type SERAs (PbSERA1, -2) and three cysteine-type SERAs (PbSERA3, -4 and -5). 

Sequence homology and syntenic organisation indicate that PbSERA3, -4 (PB000352.01.0) and -5 (PB000649.01.0) are orthologs of P. falciparum SERA6, -7, -8.

P. berghei encodes two members of the SERAser subfamily, PbSERA1 and PbSERA2. Direct sequencing of cDNA from asynchronous blood stages permitted identification of the complete coding sequences (Genbank accession numbers: EU917224 and EU917225 for PbSERA1 and PbSERA2, respectively). Comparison of the P. berghei orthologs with the founding member PfSERA5 (PFB0340c) illustrates the overall amino acid sequence similarity of ~35% to the human malaria protein.

Phenotype
The phenotype analyses indicate that SERA1 and SERA2 do not have an essential role throughout the complete life cycle. The normal development of this mutant throughout the life cycle indicates that SERA1 and SERA2 have no compensatory functions. See also mutants RMgm-367 and RMgm-368 for mutants lacking either SERA1 or SERA2.

Additional information
SERA1 and SERA2 are transcribed during formation of liver stage and blood stage merozoites. No transcription was detected in oocysts/sporozoites.
See also mutant RMgm-365 which expresses the endogenous SERA1 protein fused to the mCherry.  PbSERA1/mCherry was detected in mid and late liver stages, and localized predominantly to the parasitophorous vacuole. In contrast, SERA2/mCherry (see RMgm-366 ) became detectable only at the end of liver stage development, with an intracellular distribution in the parasite. SERA1/mCherry was not detected in merosomes, in contrast to SERA2/mCherry, which gave a strong signal associated with individual merozoites inside merosomes.
Mutants lacking both SERAs had increased levels of the cysteine-type SERA3, both at transcript and protein levels.

Other mutants
RMgm-102: A mutant lacking expression of SERA8 (PB000649.01.0; PFB0325c), a cysteine-type SERA homologue (serine repeat antigen 8, SERA-8; ECP1, egress cysteine protease 1; PbSERA5)
RMgm-271: A mutant expressing GFP under the control of the 5'-UTR of PbSERA3 (an ortholog of P. falciparum SERA6)
RMgm-272: The mutant expresses in addition to the endogenous SERA3  (the ortholog of P. falciparum SERA6) a TAP-tagged form of SERA3 under control of its own 5'-UTR and the dhfr/ts 3'-UTR
RMgm-365: A mutant expressing the endogenous SERA1 protein fused to the mCherry red fluorescent protein
RMgm-366: A mutant expressing the endogenous SERA2 protein fused to the mCherry red fluorescent protein
RMgm-367: A knock-out mutant lacking expression of SERA1
RMgm-368: A knock-out mutant lacking expression of SERA2