Polymorphisms in the Human High Sulfur Hair Keratin-associated Protein 1, KAP1, Gene Family

Yutaka Shimomura,Noriaki Aoki,Jürgen Schweizer,Lutz Langbein,Michael A Rogers,Hermelita Winter,Masaaki Ito

doi:10.1074/jbc.m206398200

Abstract

Hair fiber differentiation and maturation involves the close interaction between hair keratins and their associated proteins, KAPs. Recently, a cluster of seven human KAP multigen families has been identified on chromosome 17q12-21 among which were four hKAP1 genes (hKAP1.1B, hKAP1.3, hKAP1.4, and hKAP1.5). In addition, there were previous as well as recent reports on four additional hKAP1 genes (hKAP1.1A, hKAP1.2, hKAP1.6, and hKAP1.7) with unknown chromosomal location. In this study, we have analyzed these eight hKAP1 genes in unrelated Japanese and Caucasian individuals and discovered that hKAP1.1A, hKAP1.6, and hKAP1.7 represent size polymorphisms of the hKAP1.1B gene. In addition, we show that hKAP1.2 as well as three hitherto unknown genes (hKAP1.8A, hKAP1.8B, and hKAP1.9) are size polymorphisms of the hKAP1.3 gene. In contrast, no polymorphic alleles were found for the hKAP1.4 and hKAP1.5 genes. We provide evidence that the polymorphic hKAP1.1B and hKAP1.3 alleles arose mainly by intragenic deletion and/or duplication events of distinct pentapeptide repeats typical for hKAP1 genes. We also demonstrate the occurrence of both frequent and rare population-specific hKAP1.1B and hKAP1.3 alleles, which were obviously generated after the divergence of the Caucasian and Japanese lineage. In addition, by means of a pan-hKAP1 antibody, we confirm the previous hKAP1 family mRNA localization data in the middle to upper cortex of the human anagen hair follicle.

Highlights

Hair fiber differentiation and maturation involves the close interaction between hair keratins and their associated proteins, keratin-associated proteins (KAPs)
Identification of Polymorphisms in the hKAP1.1B Gene—To analyze the relationship between the hKAP1.1A/B, hKAP1.6, and hKAP1.7 genes, we first tried to PCR-amplify the hKAP1.1B gene using genomic DNA of eight unrelated Japanese individuals and the hKAP1.1B-specific primer KAP1.1B5Ј-1 as well as primer KAP1-3Ј-1, which is common to the four genes (Table I)
Direct sequencing showed that the larger 973-bp fragment corresponded to the hKAP1.1B gene and that the smaller 835-bp product corresponded to the hKAP1.6 gene

Summary

EXPERIMENTAL PROCEDURES

Identification of Polymorphisms in hKAP1.1B and hKAP1.3 Genes— Peripheral leukocyte DNA was prepared from consenting Japanese and Caucasian individuals using standard protocols. The hKAP1.3 gene and its polymorphic variants were PCR-amplified using hKAP1.3-specific primers (Table I) and analyzed in the same manner as stated above. After the synthesis of the first strand cDNAs using an oligo(dT)-adaptor primer derived from total RNA of anagen hair follicles of a Japanese individual who was heterozygous for hKAP1.8A and hKAP1.8B allele, PCR was performed using the adaptor primer (5Ј-GTTTCCCAGTCACGAC-3Ј) and KAP1.3-5Ј-1 primer designed at the 5Ј-noncoding region of hKAP1.3 (Table I). A pan-hKAP1 antiserum was generated in guinea pigs using the synthetic oligopeptide QEGSSGAVSTRIRWCR coupled to keyhole limpet protein (Peptide Specialty Laboratories, Heidelberg, Germany) as antigen This oligopeptide was derived from the central non-repetitive domain and is common to all hKAP1 proteins [16, 17]. Visualization and documentation were performed with a photomicroscope (Axiophot II, Carl Zeiss, Jena/Oberkochen, Germany)

RESULTS

Size of product

DISCUSSION