Mutant/mutation
The mutant expresses a GFP-tagged (c-terminal) form of BIR38. The bir38-gfp gene is introduced into the non-essential c-type ribosomal rna gene and is expressed under the control of its own 5'-UTR and pbdhfr 3'-UTR regulatory sequences.

Protein (function)
BIR38 is a member of a variant antigen family (Plasmodium interspersed repeat proteins, PIR). These proteins are potentially implicated in host immune system interactions and targeted to or on the surface of the host erythrocyte. In P. vivax there are approximately 350 pir (vir) in the genome, and homologues have been identified in Plasmodium infecting rodents and monkeys; P. berghei (bir), P. chabaudi (cir), P. yoelii (yir), P. knowlesi (kir). PIR proteins show homology to proteins which are members of the RIF/STEVOR family of P. falciparum proteins. Consistent with a role in antigenic variation and immune evasion, PIR proteins have been demonstrated on, or close to the surface membrane of erythrocytes infected with P. vivax, P. chabaudi, P. yoelii and P.berghei  and switching of yir transcription has been observed in response to a host immune response.

Phenotype
The phenotype analyses indicate that BIR38 is expressed late during the asexual blood stage cycle (late trophozoites, schizonts) and is exported to the host erythrocyte cytoplasm and is associated with cholesterol-rich microdomains (lipid rafts).

Additional information
In plasma membranes of eukaryotic cells associations of sphingolipids, cholesterol and proteins enable the formation of special microdomains that are resistant to solubilization with non-ionic detergents at low temperature. These detergent-resistant membranes, named lipid rafts, play a role in defining the specificity of trafficking of proteins and lipids to and from cellular compartments. Many raft proteins are linked to saturated acyl chains in the form of glycosylphospatidylinositol (GPI) anchor or through acylation with myristate or palmitate.

DNA sequence (unspliced) of bir38 (introns in blue):
ATGGATGATG CTCTA GTATA TACACTTTTT TATATTATAT TTCCTATAAA CTTCATTAAGTTTTATTTTA ATATCATTTT CTTAATACAT ATTTTTACCA TTTTTTTTAA ATGGTTTCTTAGTGTCAAAA CTTTGATGTT TTGATGAAGT ATTTACCTGC TGAATTAGGC GGAACCGCAAATTTTGAATT TAAACAAATT ACAAATTTCG ATAAGTACTG CCCTAATGGA GACTGCAATACTAATCTCGA AAAAATTACA ATTGGATTTT TATGGTTACT TGAACAATGT TTTTCTACACCCATAAATAA AAATCATAAT GAAAACAATA CTAATGCATA TTTTATATAT GTTGTATTATGGTTAAGTTA CAAATTAAAT CAAATAACAG GCCAAAATTT CACTAAAATA AACGATTTTTATACTAATCA AGTAAATAAT AGTGGTAAAT ATAGTAAATT TATAAGTGAT TCCAATAGATATACAAATAT TAAGGAATTC ATAGAGAAAC AAAAAGATTT GTTGAATATT AATATTGAAGATCTTTCTAA ATTTTATGAT GCATCCAAAT TAATATGTAG TATGTATGGT AATTATGCAATGAATAATAA TAACAAACTG TCAAATAATG CTACTAGTTT TGTTAACACA TATACAGAGCTTAACAATAA CTATAATACT AAAGGTACCG CATATAGTCA AATACTGTCT GCCTTATCAACTGATTATAA TAATTTAAAA AATAAATGTA GCAATATTCC AACCCTTTCA GAGATAAACACATCAAAAAA TACTGTAGAA ACTTCTGATC AAAGTCCTGA ACAAAGTGTA CAAATATTAGAACATATTTC TGAAGTTACA TCATCAAGTT CGTCGATAGG AAACAAATTA TTTACAGTTTTATCGATATT TGGTGCAATA GCATTTTTTT TAGGAATTTC TTATAAGGTA AATAATAAGGAATTAAAAAA ATATTTTCAT TATATATATG CAAGCATTAA CAAAAATACC ATACGCTTCTTAACGTTTTA TATTAGTATT CGTTATTTGG ACGTCGGAAA CGATCTCAAA AACAATATTTAAGAGAAAAA ATAAAAAATA TAAAGAAGAG AATGAATCAT TAA

Protein BIR38 (transmembrane region in pink):
MDDALCQNFD VLMKYLPAEL GGTANFEFKQ ITNFDKYCPN GDCNTNLEKI TIGFLWLLEQ CFSTPINKNH NENNTNAYFI YVVLWLSYKL NQITGQNFTK INDFYTNQVN NSGKYSKFIS DSNRYTNIKE FIEKQKDLLN INIEDLSKFY DASKLICSMY GNYAMNNNNK LSNNATSFVN TYTELNNNYN TKGTAYSQIL SALSTDYNNL KNKCSNIPTL SEINTSKNTV ETSDQSPEQS VQILEHISEV TSSSSSIGNK LFTVLSIFGA IAFFLGISYK YSLFGRRKRS QKQYLREKIK NIKKRMNH

Other mutants