Mapping the human CAS2 gene, the homologue of the mouse brown (b) locus, to human Chromosome 9p22-pter

Chintamaneni, C; Ramsay, Michèle; Colman, M.A.; Fox, Margaret; Pickard, Richard T.; Kwon, Byoung S.

doi:10.1016/0006-291x(91)91803-k

Cited by 38 publications

(10 citation statements)

References 23 publications

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“…The mouse b locus gene mapped to mouse chromosome 4 and its genomic organisation has been analysed (Shibahara et al, 1991) while the human homologue, termed CAS2, has been mapped to human chromosome 9p22-pter (Chintamaneni et al, 1991). Other workers have demonstrated that the gp75/b-locus/TRP protein has a measurable catalase activity and have speculated on the role for such an enzyme in controlling pigment production in mammals (Halaban & Moellmann, 1990).…”

Section: Discussionmentioning

confidence: 99%

“…Since the Mr of this antigen was similar to that recognised by MoAb HMSA-5, parallel immunoprecipitations with HMSA-5 and MoAb TA99 (which recognises gp75) were carried out (data not shown). Although the results obtained suggested that both antibodies were recognising a common antigen, it was difficult to make a definite conclusion based on the Mr of the two antigens since it was known that several other antigens, including tyrosinase, albumin, and the silver locus human homologue protein (Kwon et al, 1987a;Chintamaneni, 1991) also migrate into this region of SDS-PAGE gels. Parallel sequential immunodepletion experiments showed that MoAb HMSA-5 was able to pre-clear the labelled antigen recognised by MoAb TA99 and vice versa (Figure 10).…”

Section: Pulse-chase Experimentsmentioning

confidence: 97%

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A murine monoclonal antibody, MoAb HMSA-5, against a melanosomal component highly expressed in early stages, and common to normal and neoplastic melanocytes

Der

Dixon²,

Jimbow³

et al. 1993

Br J Cancer

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Summary The melanosome is a secretory organelle unique to the melanocyte and its neoplastic counterpart, malignant melanoma. The synthesis and assembly of these intracytoplasmic organelles is not yet fully understood. We have developed a murine monoclonal antibody (MoAb) against melanosomes isolated from human melanocytes (newborn foreskin) cultured in the presence of 12-0 tetradecanoyl phorbol-13-acetate (TPA). This MoAb, designated HMSA-5 (Human Melanosome-Specific Antigen-5) (IgG1), recognised a cytoplasmic antigen in both normal human melanocytes and neoplastic cells, such as common and dysplastic melanocytic nevi, and malignant melanoma. None of the carcinoma or sarcoma specimens tested showed positive reactivity with MoAb HMSA-5. Under immunoelectron microscopy, immuno-gold deposition was seen on microvesicles associated with melanosomes, and a portion of the ER-Golgi complexes. Radioimmunoprecipitation analysis showed that the HMSA-5 reactive antigen was a glycoprotein of M, 69 to 73 kDa. A pulse-chase time course study showed that the amount of antigen detected by MoAb HMSA-5 decreased over a 24 h period without significant expression on the cell surface, or corresponding appearance of the antigen in the culture supernatant. This glycoprotein appears to play a role in the early stages of melanosomal development, and the HMSA-5 reactive epitope may be lost during subsequent maturation processes. Importantly, HMSA-5 can be identified in all forms of human melanocytes, hence it can be considered a new common melanocytic marker even on routine paraffin sections.

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Section: Discussionmentioning

confidence: 99%

Section: Pulse-chase Experimentsmentioning

confidence: 97%

A murine monoclonal antibody, MoAb HMSA-5, against a melanosomal component highly expressed in early stages, and common to normal and neoplastic melanocytes

Der

Dixon²,

Jimbow³

et al. 1993

Br J Cancer

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“…Tyrp1 has been associated with numerous enzymatic activities. It was initially suggested by Halaban et al that Tyrp1 had catalase activity and the authors recommended renaming the molecule catalase-B and its gene CAS2 (37,63). Based on its homology to tyrosinase, Tyrp1 has also been speculated to be another tyrosinase or exhibit tyrosinase-like activity.…”

Section: Tyrp1 Its Functionmentioning

confidence: 99%

Tyrp1 and Oculocutaneous Albinism Type 3

Sarangarajan

Boissy

2001

Pigment Cell Research

111

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addition to its role in eumelanin synthesis, Tyrp1 is involved in Tyrosinase-related protein 1 (Tyrp1) is a melanocyte-specific maintaining stability of tyrosinase protein and modulating its gene product involved in eumelanin synthesis. Mutations in the catalytic activity. Tyrp1 is also involved in maintenance of mouse Tyrp1 gene are associated with brown pelage, and in the human TYRP1 gene with oculocutaneous albinism type 3 melanosome ultrastructure and affects melanocyte prolifera-(OCA3). In the murine system, Tyrp1 expresses significant tion and melanocyte cell death. The current review is an dihydroxyindole carboxylic acid oxidase (i.e. DHICA oxattempt to consolidate our understanding of the role of Tyrp1 idase) activity. However, in humans, TYRP1 is enigmatic in in the melanocyte. that despite extensive efforts focused on the study of its Key words: Pigmentation, Tyrosine hydroxylase, Brown/Rufunction, its actual role in the human melanocyte is still fous Albinism, Brown locus, Protein trafficking unclear. There is mounting evidence demonstrating that in Mutations in the genes encoding some of the enzymes and regulatory proteins involved in melanin synthesis result in various forms of oculocutaneous albinism (OCA). OCA1 correlates with mutations in the tyrosinase (TYR) gene (7). Most individuals with OCA1 have completely amelanotic skin, hair and eyes with the inability to tan (i.e. OCA1A). However, some nucleotide lesions of the TYR gene result in a partially functional enzyme so that individuals with this subtype of OCA1 can exhibit moderate levels of skin and hair pigmentation and the ability to tan (i.e. OCA1B). OCA2 correlates with mutations in the P gene (8). Individuals with OCA2 present with minimal to moderate amounts of pigment remaining in the skin, hair and eyes, many of whom can develop pigmented freckles, lentigines and/or nevi with age. OCA3 correlates with mutations in the TYRP1 gene (9). Individuals with OCA3 present with minimal pigment reduction in the skin, hair and eyes. This form of albinism was previously referred to as Rufous and possibly some forms of Brown albinism.

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“…mapped to the murine brown locus (2,4) and the human homolog was localized on chromosome 9p23 (5)(6)(7). TRP-1 is a relatively abundant 75 kDa glycoprotein synthesized only by melanocytes and is primarily localized to the limiting membrane of the melanosome (8)(9)(10).…”

mentioning

confidence: 99%

Human tyrosinase related protein‐1 (TRP‐1) does not function as a DHICA oxidase activity in contrast to murine TRP‐1

Boissy¹,

Sakai²,

Zhao³

et al. 1998

Experimental Dermatology

118

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Tyrosinase related protein-1 is a melanocyte specific protein and a member of the tyrosinase gene family which also includes tyrosinase and TRP 2 (DOPAchrome tautomerase). In murine melanocytes, TRP-1 functions as a 5,6-dihydroxyindole-2-carboxylic acid [DHICA] oxidase during the biosynthetic conversion of tyrosine to eumelanin and mutations affecting TRP-1 result in the synthesis of brown rather than black pelage coloration. In this study, we examined the putative DHICA oxidase activity of TRP-1 in human melanocytes using several approaches. We first utilized a line of cultured melanocytes established from a patient with a form of oculocutaneous albinism completely lacking expression of TRP-1 (OCA3). This line of melanocytes endogenously exhibited the same amount of DHICA oxidase activity as control melanocytes expressing TRP-1. In other experiments, cultured human fibroblasts were transfected with a cDNA for TRP-1, in either the sense or antisense direction, or with the retroviral vector alone. TRP-1 expression was induced in fibroblasts transfected with the TRP-1 cDNA in the sense direction only. Although TRP-1 was expressed by sense-transfected cells, there was no significant DHICA oxidase activity above controls. These results demonstrate that human TRP-1 does not use DHICA as a substrate for oxidation.

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Mapping the human CAS2 gene, the homologue of the mouse brown (b) locus, to human Chromosome 9p22-pter

Cited by 38 publications

References 23 publications

A murine monoclonal antibody, MoAb HMSA-5, against a melanosomal component highly expressed in early stages, and common to normal and neoplastic melanocytes

A murine monoclonal antibody, MoAb HMSA-5, against a melanosomal component highly expressed in early stages, and common to normal and neoplastic melanocytes

Tyrp1 and Oculocutaneous Albinism Type 3

Human tyrosinase related protein‐1 (TRP‐1) does not function as a DHICA oxidase activity in contrast to murine TRP‐1

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