scholarly journals A tyrosinase gene missense mutation in temperature-sensitive type I oculocutaneous albinism. A human homologue to the Siamese cat and the Himalayan mouse.

1991 ◽  
Vol 87 (3) ◽  
pp. 1119-1122 ◽  
Author(s):  
L B Giebel ◽  
R K Tripathi ◽  
R A King ◽  
R A Spritz
Keyword(s):  
Missense Mutation ◽  
Oculocutaneous Albinism ◽  
Temperature Sensitive ◽  
Type I ◽  
Human Homologue ◽  
Tyrosinase Gene ◽  
Siamese Cat

scholarly journals Identification of a missense mutation in the tyrosinase gene in a Chinese family with oculocutaneous albinism type 1

2017 ◽  
Vol 15 (3) ◽  
pp. 1426-1430 ◽  
Author(s):  
Qian Lu ◽  
Lamei Yuan ◽  
Hongbo Xu ◽  
Xiangjun Huang ◽  
Zhijian Yang ◽  
...  
Keyword(s):  
Missense Mutation ◽  
Oculocutaneous Albinism ◽  
Chinese Family ◽  
Tyrosinase Gene

scholarly journals Type I Oculocutaneous Albinism Associated with a Full-Length Deletion of the Tyrosinase Gene

1996 ◽  
Vol 106 (5) ◽  
pp. 1137-1140 ◽  
Author(s):  
Rhonda E. Schnur ◽  
Beatrice T. Sellinger ◽  
Stuart A. Holmes ◽  
Penelope A. Wick ◽  
Yvonne O. Tatsumura ◽  
...  
Keyword(s):  
Oculocutaneous Albinism ◽  
Full Length ◽  
Type I ◽  
Tyrosinase Gene

Tyrosinase gene mutations in type I (tyrosinase-deficient) oculocutaneous albinism define two clusters of missense substitutions

1992 ◽  
Vol 43 (5) ◽  
pp. 865-871 ◽  
Author(s):  
Ram K. Tripathi ◽  
Kathleen M. Strunk ◽  
Lutz B. Giebel ◽  
Richard G. Weleber ◽  
Richard A. Spritz
Keyword(s):  
Gene Mutations ◽  
Oculocutaneous Albinism ◽  
Type I ◽  
Tyrosinase Gene

scholarly journals Five Novel Mutations in Tyrosinase Gene of Japanese and Indian Patients with Oculocutaneous Albinism Type I (OCA1)

2005 ◽  
Vol 125 (2) ◽  
pp. 397-398 ◽  
Author(s):  
Yoshinori Miyamura ◽  
Ishwar C. Verma ◽  
Renu Saxena ◽  
Michiko Hoshi ◽  
Ayumi Murase ◽  
...  
Keyword(s):  
Oculocutaneous Albinism ◽  
Type I ◽  
Novel Mutations ◽  
Tyrosinase Gene ◽  
Indian Patients

The molecular basis of oculocutaneous albinism type 1 (OCA1): sorting failure and degradation of mutant tyrosinases results in a lack of pigmentation

2001 ◽  
Vol 355 (2) ◽  
pp. 259-269 ◽  
Author(s):  
Kazutomo TOYOFUKU ◽  
Ikuo WADA ◽  
Richard A. SPRITZ ◽  
Vincent J. HEARING
Keyword(s):  
Molecular Basis ◽  
Control Process ◽  
Large Deletion ◽  
Oculocutaneous Albinism ◽  
Temperature Sensitive ◽  
Tyrosinase Gene ◽  
Catalytic Function ◽  
Quality Control Process ◽  
Early Processing

Oculocutaneous albinism type 1 (OCA1) is an autosomal recessive disease resulting from mutations of the tyrosinase gene (TYR). To elucidate the molecular basis of OCA1 phenotypes, we analysed the early processing and maturation of several different types of mutant tyrosinase with various degrees of structural abnormalities (i.e. two large deletion mutants, two missense mutants that completely destroy catalytic function and three missense mutants that have a temperature-sensitive phenotype). When expressed in COS7 cells, all mutant tyrosinases were sensitive to endoglycosidase H digestion, and immunostaining showed their localization in the endoplasmic reticulum (ER) and their failure to be sorted further to their target organelles. Pulse-chase experiments showed that all mutant tyrosinases were retained by calnexin in the ER and that they were degraded at similarly rapid rates, which coincided with their dissociation from calnexin. Temperature-sensitive mutant enzymes were sorted more efficiently at 31°C than at 37°C, and their degradation was accelerated at 37°C compared with 31°C. Thus in contrast to the current concept that mutant tyrosinases are transported to melanosomes but are functionally inactive there, our results suggest that mutant tyrosinases may not be transported to melanosomes in the first place. We conclude that a significant component of mutant tyrosinase malfunction in OCA1 results from their retention and degradation in the ER compartment. This quality-control process is highly sensitive to minimal changes in protein folding, and so even relatively minor mutations in peripheral sequences of the enzyme not involved with catalytic activity may result in a significant reduction of functional enzyme in melanosomes.

scholarly journals Baboon bearing resemblance in pigmentation pattern to Siamese cat carries a missense mutation in the tyrosinase gene

Genome ◽  
2020 ◽  
Vol 63 (5) ◽  
pp. 275-279 ◽  
Author(s):  
Akihiko Koga ◽  
Chiemi Hisakawa ◽  
Miki Yoshizawa
Keyword(s):  
Distal Portion ◽  
Base Substitution ◽  
Temperature Sensitive ◽  
Hamadryas Baboon ◽  
Copper Binding ◽  
Pigmentation Pattern ◽  
Tyrosinase Gene ◽  
Siamese Cat ◽  
Albino Phenotype ◽  
Tyr Gene

An infant hamadryas baboon exhibiting an albino phenotype—white body hair and red eyes—was born to parents with wild-type body color. Pigmentation on some parts of its body surfaced during childhood and progressed with age. This baboon in adulthood has gray hair on parts of its body, such as the tail, distal portion of the legs, and face, with the remainder being white. This pigmentation pattern resembles that of the Siamese cat and the Himalayan variants of the mouse and the mink. The distinguishing phenotypes in these animals are known to be caused by a temperature-sensitive activity of tyrosinase, an enzyme essential for biosynthesis of melanin. We sequenced all the five exons of the tyrosinase (TYR) gene of this albino baboon, which were amplified by PCR, and found a base substitution leading to alteration of the 365th amino acid from Ala to Thr. Tyrosinase requires copper as a cofactor for its enzyme function. It has two copper-binding sites, the second of which contains His residues in positions 363 and 367 that are critical to its function. Thus, p.(Ala365Thr) due to a mutation in the TYR gene is a likely candidate for the cause of the albino phenotype in this baboon.

Sign in / Sign up

Export Citation Format

Share Document