Phenotypic Mutation 'Titan' (pdf version)
AlleleTitan
Mutation Type critical splice donor site (2 bp from exon)
Chromosome7
Coordinate46,432,893 bp (GRCm39)
Base Change A ⇒ G (forward strand)
Gene Hps5
Gene Name HPS5, biogenesis of lysosomal organelles complex 2 subunit 2
Synonym(s) Hermansky-Pudlak syndrome 5, ru-2, ru2, ruby eye 2
Chromosomal Location 46,409,890-46,445,488 bp (-) (GRCm39)
MGI Phenotype FUNCTION: [Summary is not available for the mouse gene. This summary is for the human ortholog.] This gene encodes a protein that may play a role in organelle biogenesis associated with melanosomes, platelet dense granules, and lysosomes. This protein interacts with Hermansky-Pudlak syndrome 6 protein and may interact with the cytoplasmic domain of integrin, alpha-3. Mutations in this gene are associated with Hermansky-Pudlak syndrome type 5. Multiple transcript variants encoding two distinct isoforms have been identified for this gene. [provided by RefSeq, Jul 2008]
PHENOTYPE: Homozygotes have hypopigmented eyes and hair, impaired secretion of lysosomal enzymes by renal proximal tubules and reduced clotting due to a platelet dense granule defect. Homozygotes for one allele are less susceptible to diet-induced atherosclerosis. [provided by MGI curators]
Accession Number

NCBI RefSeq: NM_001005247, NM_001167864; MGI: 2180307

MappedYes 
Amino Acid Change
Institutional SourceBeutler Lab
Gene Model predicted gene model for protein(s): [ENSMUSP00000014562 ] [ENSMUSP00000103280 ] [ENSMUSP00000103281 ] [ENSMUSP00000116770] [ENSMUSP00000122887 ] [ENSMUSP00000147450 ] [ENSMUSP00000115786]   † probably from a misspliced transcript
AlphaFold P59438
SMART Domains Protein: ENSMUSP00000014562
Gene: ENSMUSG00000014418

DomainStartEndE-ValueType
SCOP:d1jjub_ 44 192 3e-8 SMART
Blast:WD40 63 103 7e-21 BLAST
Blast:WD40 111 151 1e-19 BLAST
low complexity region 429 449 N/A INTRINSIC
low complexity region 775 786 N/A INTRINSIC
low complexity region 989 998 N/A INTRINSIC
low complexity region 1021 1033 N/A INTRINSIC
Predicted Effect probably null
SMART Domains Protein: ENSMUSP00000103280
Gene: ENSMUSG00000014418

DomainStartEndE-ValueType
SCOP:d1jjub_ 44 192 3e-8 SMART
Blast:WD40 63 103 6e-21 BLAST
Blast:WD40 111 151 1e-19 BLAST
low complexity region 396 416 N/A INTRINSIC
low complexity region 742 753 N/A INTRINSIC
low complexity region 956 965 N/A INTRINSIC
low complexity region 988 1000 N/A INTRINSIC
Predicted Effect probably null
SMART Domains Protein: ENSMUSP00000103280
Gene: ENSMUSG00000014418

DomainStartEndE-ValueType
SCOP:d1jjub_ 44 192 3e-8 SMART
Blast:WD40 63 103 6e-21 BLAST
Blast:WD40 111 151 1e-19 BLAST
low complexity region 396 416 N/A INTRINSIC
low complexity region 742 753 N/A INTRINSIC
low complexity region 956 965 N/A INTRINSIC
low complexity region 988 1000 N/A INTRINSIC
Predicted Effect probably null
SMART Domains Protein: ENSMUSP00000103281
Gene: ENSMUSG00000014418

DomainStartEndE-ValueType
SCOP:d1jjub_ 44 192 3e-8 SMART
Blast:WD40 63 103 7e-21 BLAST
Blast:WD40 111 151 1e-19 BLAST
low complexity region 429 449 N/A INTRINSIC
low complexity region 775 786 N/A INTRINSIC
low complexity region 989 998 N/A INTRINSIC
low complexity region 1021 1033 N/A INTRINSIC
Predicted Effect probably null
SMART Domains Protein: ENSMUSP00000103281
Gene: ENSMUSG00000014418

DomainStartEndE-ValueType
SCOP:d1jjub_ 44 192 3e-8 SMART
Blast:WD40 63 103 7e-21 BLAST
Blast:WD40 111 151 1e-19 BLAST
low complexity region 429 449 N/A INTRINSIC
low complexity region 775 786 N/A INTRINSIC
low complexity region 989 998 N/A INTRINSIC
low complexity region 1021 1033 N/A INTRINSIC
Predicted Effect probably null
SMART Domains Protein: ENSMUSP00000116770
Gene: ENSMUSG00000014418

DomainStartEndE-ValueType
SCOP:d1tbga_ 24 107 5e-4 SMART
Blast:WD40 63 103 1e-22 BLAST
Predicted Effect probably benign
SMART Domains Protein: ENSMUSP00000122887
Gene: ENSMUSG00000014418

DomainStartEndE-ValueType
SCOP:d1jjub_ 44 192 8e-8 SMART
Blast:WD40 63 103 9e-20 BLAST
Blast:WD40 111 151 2e-19 BLAST
low complexity region 429 449 N/A INTRINSIC
Predicted Effect probably benign
Predicted Effect probably benign
Predicted Effect probably benign
SMART Domains Protein: ENSMUSP00000115786
Gene: ENSMUSG00000014418

DomainStartEndE-ValueType
SCOP:d1jjub_ 44 192 2e-8 SMART
Blast:WD40 63 103 1e-21 BLAST
Blast:WD40 111 151 2e-20 BLAST
Predicted Effect probably benign
Meta Mutation Damage Score 0.9591 question?
Is this an essential gene? Probably nonessential (E-score: 0.104) question?
Phenotypic Category Autosomal Recessive
Candidate Explorer Status loading ...
Single pedigree
Linkage Analysis Data
Penetrance  
Alleles Listed at MGI

All mutations/alleles(77) : Chemically induced (ENU)(3) Gene trapped(66) Spontaneous(6) Targeted(2)

Lab Alleles
AlleleSourceChrCoordTypePredicted EffectPPH Score
IGL00089:Hps5 APN 7 46425362 missense probably damaging 1.00
IGL00543:Hps5 APN 7 46427497 missense probably benign 0.37
IGL01090:Hps5 APN 7 46437751 missense probably benign 0.02
IGL01351:Hps5 APN 7 46410856 missense probably damaging 1.00
IGL01479:Hps5 APN 7 46412366 critical splice donor site probably null
IGL02056:Hps5 APN 7 46437606 missense probably damaging 1.00
IGL02117:Hps5 APN 7 46432940 missense probably damaging 1.00
IGL02210:Hps5 APN 7 46435994 missense probably benign 0.03
IGL02967:Hps5 APN 7 46418804 missense possibly damaging 0.69
IGL03046:Hps5 APN 7 46426463 splice site probably benign
IGL03187:Hps5 APN 7 46422631 missense probably damaging 1.00
IGL03259:Hps5 APN 7 46412526 missense probably damaging 0.99
dorian_gray UTSW 7 46784145 unclassified probably benign
smoky UTSW 7 46418775 nonsense probably null
toffee UTSW 7 46777075 intron probably benign
wombat UTSW 7 46433058 missense probably damaging 1.00
R0068:Hps5 UTSW 7 46426466 splice site probably benign
R0068:Hps5 UTSW 7 46426466 splice site probably benign
R0141:Hps5 UTSW 7 46438605 missense probably damaging 1.00
R0383:Hps5 UTSW 7 46418712 splice site probably null
R0402:Hps5 UTSW 7 46440333 splice site probably benign
R0684:Hps5 UTSW 7 46432893 critical splice donor site probably null
R1159:Hps5 UTSW 7 46421978 splice site probably null
R1938:Hps5 UTSW 7 46422691 missense probably damaging 1.00
R2058:Hps5 UTSW 7 46417475 missense probably damaging 1.00
R3613:Hps5 UTSW 7 46426298 critical splice donor site probably null
R3881:Hps5 UTSW 7 46421420 missense possibly damaging 0.54
R3882:Hps5 UTSW 7 46421420 missense possibly damaging 0.54
R3914:Hps5 UTSW 7 46432950 missense probably damaging 1.00
R4095:Hps5 UTSW 7 46425218 missense probably benign 0.01
R4457:Hps5 UTSW 7 46433037 missense probably benign 0.00
R4739:Hps5 UTSW 7 46436013 missense probably benign
R4838:Hps5 UTSW 7 46437778 missense probably damaging 1.00
R4934:Hps5 UTSW 7 46418775 nonsense probably null
R5876:Hps5 UTSW 7 46438620 missense probably damaging 1.00
R6056:Hps5 UTSW 7 46416521 missense probably benign 0.00
R6129:Hps5 UTSW 7 46421198 missense probably benign
R6878:Hps5 UTSW 7 46433058 missense probably damaging 1.00
R7912:Hps5 UTSW 7 46418826 missense probably benign 0.15
R7977:Hps5 UTSW 7 46418475 missense probably benign 0.03
R7987:Hps5 UTSW 7 46418475 missense probably benign 0.03
R8131:Hps5 UTSW 7 46421312 missense probably benign 0.00
R8243:Hps5 UTSW 7 46436066 missense probably damaging 1.00
R8245:Hps5 UTSW 7 46418485 nonsense probably null
R8878:Hps5 UTSW 7 46421345 missense probably benign 0.07
R9050:Hps5 UTSW 7 46422607 missense probably benign 0.00
R9186:Hps5 UTSW 7 46438370 missense probably damaging 1.00
R9278:Hps5 UTSW 7 46440397 missense probably benign 0.00
R9290:Hps5 UTSW 7 46424331 missense probably damaging 0.97
R9303:Hps5 UTSW 7 46438619 missense possibly damaging 0.94
R9305:Hps5 UTSW 7 46438619 missense possibly damaging 0.94
R9650:Hps5 UTSW 7 46425354 missense probably damaging 1.00
X0021:Hps5 UTSW 7 46412517 missense probably damaging 1.00
Mode of Inheritance Autosomal Recessive
Local Stock Live Mice
MMRRC Submission 038259-MU
Last Updated 2019-09-04 9:49 PM by Diantha La Vine
Record Created 2014-01-07 9:48 AM by Carlos Reyna
Record Posted 2015-01-13
Phenotypic Description
Figure 1. Phenotype of the titan mice.

The titan phenotype was identified among ENU-mutagenized G3 mice of the pedigree R0684, some of which showed hypopigmentation of the fur, pale colored ears, and pink feet and tail (Figure 1). The titan mice resemble mice of the ruby-eye 2 (ru2) strain (1).

Nature of Mutation

Whole exome HiSeq sequencing of the G1 grandsire identified 52 mutations.  A mutation in Hps5 was presumed to be causative because the titan phenotype mirrored the dorian gray and toffee phenotypes attributed to Hps5. The mutation in Hps5 is a T to C transition at base pair 46,783,469 (v38) on chromosome 7, or base pair 113,685 in the GenBank genomic region NC_000073.  The mutation is located within the donor splice site of intron 7, two nucleotides from the previous exon. Hps5 contains 23 total exons. The effect of the mutation at the cDNA and protein level is unknown. One possibility, shown below, is that aberrant splicing may result in skipping of the 213 base pair exon 7 and in-frame splicing from exon 6 to exon 8. This would result in deletion of 70 amino acids in the HPS5 protein; the deletion is not within a defined domain.

            <--exon 6        <--exon 7 intron 7-->     exon 8-->                <--exon 23

9542 ……TGTGACACCGAGAG ……GTGATCACTGCAAG gtagccgctacat…… ATCAGAGCCTCAGTAT…………TCGCAGCAGGCCTAG
200  ……-C--D--T--E--R ……-V--I--T--A--R                 --S--E--P--Q--Y-…………-S--Q--Q--A--*-
          correct           deleted                                    correct

Genomic numbering corresponds to NC_000073. The donor splice site of intron 7, which is destroyed by the mutation, is indicated in blue; the mutated nucleotide is indicated in red.

Illustration of Mutations in
Gene & Protein
Protein Prediction

Figure 2. A, Predicted domains of HPS5. HPS5 contains two putative WD40 domains located at amino acids 65-105 and 113-153. The titan mutation, located in intron 7, results in deletion of exon 7 and in-frame splicing from exon 6 to exon 8. This image is interactive. Click on the image to view other mutations found in HPS5. Click on each mututation for more specific information. B, Components of the biogenesis of lysosomal-related organelle complex 2 (BLOC-2). All three proteins have been shown to co-immunoprecipitate, but only HSP5 and HSP6 bind together in two-hybrid studies suggesting the presence of unknown components of the complex (?).

HPS5 is an 1126 amino acid protein that forms part of the biogenesis of lysosome-related organelle complex 2 (BLOC-2; Figure 2). Other than the putative presence (with low statistical likelihood) of two WD40 domains at amino acids 65-105 and 113-153, sequence analysis of HPS5 reveals no known protein domains. The titan mutation does not occur within a defined domain in HPS5; the expression and localization of the HPS5titan protein have not been examined.

Please see the record for toffee for more information about Hps5.

Putative Mechanism

The precise molecular function of the BLOC-2 complex remains unknown. In addition to a yet undefined role in regulating lysosome and lysosome-related organelle secretion, HPS5 may also regulate protein trafficking during the maturation of melanosomes. Mutations of HPS5 were identified as the cause of the ruby-eye 2 (ru2) phenotype in mice and Hermansky-Pudlak syndrome 5 (HPS5; OMIM #614074) in humans. The mutant ruby-eye 2 phenotype in mice was named for its resemblance to the ruby-eye phenotype, characterized by diluted coat color that darkens with age, colorless eyes that darken with age to a ruby or maroon color, and platelet storage pool deficiency that causes prolonged bleeding time (2-4). HPS (OMIM #203300) was first described in 1959, and is now known to be a heterogeneous disorder with an array of clinical symptoms caused by alterations at numerous independent loci. HPS is characterized by oculocutaneous albinism (OCA), prolonged bleeding, and pulmonary fibrosis, conditions that arise from defects in the biogenesis and/or function of so-called lysosome-related organelles, such as melanosomes and platelet dense granules (5). Most of the genes associated with HPS encode subunits of protein complexes involved in intracellular trafficking. The phenotype of the titan mouse indicates that the mutant HPS5titan protein has impaired function leading to hypopigmentation in the mouse.

Primers PCR Primer
Titan_pcr_F: CCTAAGATGCAAGAGTTTGGGGAATGC
Titan_pcr_R: ACAGGGTAACCATCCGTGCCATTG

Sequencing Primer
Titan_seq_F: TCATACTGAGGCTCTGATCTAGAAGG
Titan_seq_R: GTAGGTAAACCACCTTTGTCTTTG
Genotyping

PCR program

1) 94°C 2:00
2) 94°C 0:30
3) 55°C 0:30
4) 72°C 1:00
5) repeat steps (2-4) 40x
6) 72°C 10:00
7) 4°C hold


The following sequence of 705 nucleotides is amplified (chromosome 7, - strand):


1   acagggtaac catccgtgcc attgttttct agtgtagtac tggcagagca gaaagaggaa
61  aagggcattg tgggtagggt tatatggcca tgttgaatgt gagtgctttg acatttcttt
121 tttttgtagg taaaccacct ttgtctttgt ttctggaaat tagggaaaag ttttggaaaa
181 tcggaaataa ggaaagacat ggagaatatg gggcttgttt cttccccggg cggtgtgctg
241 ggggccagca gcctgtgatc tactgcgccc gcccaggctc ccggatgtgg gaagtgaact
301 ttgacgggga agtgctcagt acacaccagt tcaagaagct cctgtcaatg ccacccctcc
361 ctgtgatcac tgcaaggtag ccgctacatg ggacttcctg gagacactgc cttaaaattg
421 gtggtgttgt gggctggtca agatttgatt ctaccttcta agagtgagat agaatcttta
481 ttaagagatt cagagaaacc aggagagtcc ttaagcaact gtctttcttg tgattagagt
541 ggcttgagaa ggggagatgt gatttaggtg tgtgaatttg tcaatgcttt taagttgtga
601 ttacatcgtt agctggtgtg tttaccttct agatcagagc ctcagtatga tcacacagtt
661 ggatcctccc agtctttggc attccccaaa ctcttgcatc ttagg


Primer binding sites are underlined and the sequencing primers are highlighted; the mutated nucleotide is shown in red.

References
Science Writers Anne Murray
Illustrators Peter Jurek
AuthorsCarlos Reyna Tiana Purrington