Fukuzawa T .

	FIGURE 1. The time of melanin appearance in the eyes and melanophores in the periodic albino mutant is later than that of the wild type. (a–d) Stage 33/34 embryos; (e–h) stage 41 embryos; (i) adult frogs. Photographs of (c), (d), (g) and (h) are enlarged images of the head and trunk regions in (a), (b), (e) and (f), respectively. (a, c, e, g, i) Wild‐type Xenopus laevis; (b, d, f, h, i) mutant X. laevis. Melanin appears in the eyes (c, arrow) and melanophores (c, arrowheads) at stage 33/34 in the wild type (a, c), but not in the mutant (b, d). Small amounts of melanin begin to appear in the eyes (h, arrow) and melanophores (h, arrowheads) at stage 41 in the mutant (f, h). Although melanin‐containing cells do not disappear in the wild type even after metamorphosis, they almost disappear during metamorphosis in the mutant (i)
	FIGURE 2. The hps4 gene is present only in chromosome 1L, and a 1.9 kb genomic deletion including two exons in the hps4.L gene occurs in the periodic albino mutant. (a) Schematic representation of Xenopus laevis genes in chromosome 1L containing hps4 locus and in chromosome 1S (v9.2, Xenbase). (b) Alignment of DNA sequences between hps4.L region in chromosome 1L and the corresponding position in chromosome 1S. (c) Schematic representation of hps4.L gene in the wild type and in the mutant. Wild‐type hps4.L gene consists of 13 exons interrupted by 12 introns. DNA chromatograms show a 1.9 kb deletion between introns 6 and 8 in the hps4.L gene in the mutant (c, arrowheads). Accession numbers: +/+ hps4.L gene between exons 6 and 9, LC577764 (DDBJ); ap/ap hps4.L gene between exons 6 and 9, LC577765 (DDBJ)
	FIGURE 3. Deletion of two exons in the hps4.L gene in the periodic albino mutant leads to a truncated Hps4 protein. Transcripts and inferred amino acid sequences of Hps4.L in the wild type (a) and the mutant (b) are shown. In the wild type, 13 exons of hps4.L gene are transcribed and translated. In contrast, deletion of exons 7 and 8 (b, arrowhead) in hps4.L creates a premature stop codon (b, asterisk) in the mutant, resulting in a truncated Hps4 protein. Mutant Hps4 protein consists of 214 amino acids (b), which is much shorter than the wild‐type Hps4 protein consisting of 683 amino acids (a). Accession numbers: +/+ hps4.L, LC577762 (DDBJ); ap/ap hps4.L, LC577763 (DDBJ)
	FIGURE 4. Injection of wild‐type hps4.L mRNA, but not mutant hps4.L mRNA, into mutant embryos rescued the albino phenotype. (a–c) Stage 33/34 embryos; (d–h) stage 40 embryos. Uninjected control embryos of the wild type (a, d) and the mutant (b, e) were compared with mutant embryos injected with either mutant hps4.L mRNA (f) or wild‐type hps4.L mRNA (c, g, h). Although melanin did not appear in mutant control embryos at stages 33/34 (b) and 40 (e), mutant embryos injected with wild‐type hps4.L mRNA expressed melanin in the eyes (black arrows) and melanophores (arrowheads) at stages 33/34 (c) and 40 (g, h). The expression of melanin in mutant embryos injected with wild‐type hps4.L mRNA (c, g) was similar to that of wild‐type controls (a, d). Embryos injected with mutant hps4.L mRNA did not express melanin at stage 40 (f), and were similar to mutant controls (e). Dorsal view of the head and trunk regions of mutant embryo injected with wild‐type hps4.L mRNA shows that melanin appeared in the eye of the injected area (h, black arrow), but not in the eye of the uninjected area (h, white arrow)

Anderson, Hermansky-Pudlak syndrome type 4 (HPS-4): clinical and molecular characteristics. 2003, Pubmed

Anderson, Hermansky-Pudlak syndrome type 4 (HPS-4): clinical and molecular characteristics. 2003, Pubmed
Bachli, Hermansky-Pudlak syndrome type 4 in a patient from Sri Lanka with pulmonary fibrosis. 2004, Pubmed
Bagnara, Common origin of pigment cells. 1979, Pubmed
Bluemink, Ultrastructural evidence for the absence of premelanosomes in eggs of the albino mutant (ap) ofXenopus laevis. 1975, Pubmed
Carmona-Rivera, A divalent interaction between HPS1 and HPS4 is required for the formation of the biogenesis of lysosome-related organelle complex-3 (BLOC-3). 2013, Pubmed
Carmona-Rivera, Clinical, molecular, and cellular features of non-Puerto Rican Hermansky-Pudlak syndrome patients of Hispanic descent. 2011, Pubmed
Chiang, The Hermansky-Pudlak syndrome 1 (HPS1) and HPS4 proteins are components of two complexes, BLOC-3 and BLOC-4, involved in the biogenesis of lysosome-related organelles. 2003, Pubmed
Daly, snow white, a zebrafish model of Hermansky-Pudlak Syndrome type 5. 2013, Pubmed
Fukuzawa, Further studies on the melanophores of periodic albino mutant of Xenopus laevis. 1986, Pubmed , Xenbase
Fukuzawa, Unusual leucophore-like cells specifically appear in the lineage of melanophores in the periodic albino mutant of Xenopus laevis. 2004, Pubmed , Xenbase
Fukuzawa, Melanophore lineage and clonal organization of the epidermis in Xenopus embryos as revealed by expression of a biogenic marker, GFP. 2000, Pubmed , Xenbase
Fukuzawa, Periodic albinism of a widely used albino mutant of Xenopus laevis caused by deletion of two exons in the Hermansky-Pudlak syndrome type 4 gene. 2021, Pubmed , Xenbase
Fukuzawa, Unusual development of light-reflecting pigment cells in intact and regenerating tail in the periodic albino mutant of Xenopus laevis. 2010, Pubmed , Xenbase
Fukuzawa, Ferritin H subunit gene is specifically expressed in melanophore precursor-derived white pigment cells in which reflecting platelets are formed from stage II melanosomes in the periodic albino mutant of Xenopus laevis. 2015, Pubmed , Xenbase
Gerondopoulos, BLOC-3 mutated in Hermansky-Pudlak syndrome is a Rab32/38 guanine nucleotide exchange factor. 2012, Pubmed
Guttentag, Defective surfactant secretion in a mouse model of Hermansky-Pudlak syndrome. 2005, Pubmed
Hoperskaya, The development of animals homozygous for a mutation causing periodic albinism (ap) in Xenopus laevis. 1975, Pubmed , Xenbase
Hoperskaya, Induction - the main principle of melanogenesis in early development. 1981, Pubmed , Xenbase
Kloer, Assembly of the biogenesis of lysosome-related organelles complex-3 (BLOC-3) and its interaction with Rab9. 2010, Pubmed
Li, A deletion in the Hermansky-Pudlak syndrome 4 (Hps4) gene appears to be responsible for albinism in channel catfish. 2017, Pubmed
MacMillan, An analysis of pigment cell development in the periodic albino mutant of Xenopus. 1979, Pubmed , Xenbase
MacMillan, Iridophore development in wild-type and periodic albino Xenopus larvae. 1981, Pubmed , Xenbase
Marks, Lysosome-related organelles: unusual compartments become mainstream. 2013, Pubmed
Martina, BLOC-3, a protein complex containing the Hermansky-Pudlak syndrome gene products HPS1 and HPS4. 2003, Pubmed
Matsuda, A New Nomenclature of Xenopus laevis Chromosomes Based on the Phylogenetic Relationship to Silurana/Xenopus tropicalis. 2015, Pubmed , Xenbase
Nakayama, no privacy, a Xenopus tropicalis mutant, is a model of human Hermansky-Pudlak Syndrome and allows visualization of internal organogenesis during tadpole development. 2017, Pubmed , Xenbase
Nazarian, Biogenesis of lysosome-related organelles complex 3 (BLOC-3): a complex containing the Hermansky-Pudlak syndrome (HPS) proteins HPS1 and HPS4. 2003, Pubmed
Nguyen, Melanosome morphologies in murine models of hermansky-pudlak syndrome reflect blocks in organelle development. 2002, Pubmed
Ohishi, The BLOC-3 subunit HPS4 is required for activation of Rab32/38 GTPases in melanogenesis, but its Rab9 activity is dispensable for melanogenesis. 2019, Pubmed
Osanai, Rab38 Mutation and the Lung Phenotype. 2018, Pubmed
Raposo, Melanosomes--dark organelles enlighten endosomal membrane transport. 2007, Pubmed
Seldenrijk, A comparative ultrastructural and physiological study on melanophores of wild-type and periodic albino mutants of Xenopus laevis. 1982, Pubmed , Xenbase
Session, Genome evolution in the allotetraploid frog Xenopus laevis. 2016, Pubmed , Xenbase
Suzuki, Hermansky-Pudlak syndrome is caused by mutations in HPS4, the human homolog of the mouse light-ear gene. 2002, Pubmed
Wei, Hermansky-Pudlak syndrome: pigmentary and non-pigmentary defects and their pathogenesis. 2013, Pubmed
Wu, A novel mutation causes Hermansky-Pudlak syndrome type 4 with pulmonary fibrosis in 2 siblings from China. 2019, Pubmed