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The KRT77 gene is a type II epithelial cell α-keratin gene family member that plays a crucial role in animal epidermal and coat formation. This study aimed to investigate the relationship between the KRT77 gene and the adaptability of Chinese cattle in varying environments by exploring the distribution of an exon insertion of the KRT77 gene in different cattle populations. Our analysis involved amplifying and sequencing DNA samples from 362 individuals from 24 cattle breeds in China. Our findings reveal a gradual increase in the frequency of insertion from the northwest to the southeast population. We conducted an association analysis between the genotypes and climate data, revealing a correlation between the insertion and local annual mean temperature, relative humidity, and temperature humidity index. The study highlights the significance of the newly identified KRT77 gene insertion as a variation associated with environmental adaptation in Chinese cattle.This insertion variation increased insights into the genetic mechanisms that drive adaptation in Chinese cattle, emphasizing the importance of the 30-bp insertion in the KRT77 gene. Our findings facilitate further research to improve cattle breeding strategies for adaptability to changing environments from the northwest to the southeast population. In conclusion, this study provides value.

A 3-months old Chinese shar-pei puppy with ichthyosis was investigated. The dog showed generalized scaling, alopecia and footpad lesions. Histopathological examinations demonstrated a non-epidermolytic hyperkeratosis. The parents of the affected puppy did not show any skin lesions. A trio whole genome sequencing analysis identified a heterozygous de novo 3 bp deletion in the KRT1 gene in the affected dog. This variant, NM_001003392.1:c.567_569del, is predicted to delete a single asparagine from the conserved coil 1A motif within the rod domain of KRT1, NP_001003392.1:p.(Asn190del). Immunohistochemistry demonstrated normal levels of KRT1 expression in the epidermis and follicular epithelia. This might indicate that the variant possibly interferes with keratin dimerization or another function of KRT1. Missense variants affecting the homologous asparagine residue of the human KRT1 cause epidermolytic hyperkeratosis. Histologically, the investigated Chinese shar-pei showed a non-epidermolytic ichthyosis. The finding of a de novo variant in an excellent functional candidate gene strongly suggests that KRT1:p.Asn190del caused the ichthyosis phenotype in the affected Chinese shar-pei. To the best of our knowledge, this is the first description of a KRT1-related non-epidermolytic ichthyosis in domestic animals., Competing Interests: The authors have declared that no competing interests exist.

Butterfly hillstream loach (Beaufortia kweichowensis), a benthic fish in the torrential mountain streams, possesses a totally flat ventrum, flattened craniofacial and body skeletons, and enlarged paired fins covered by substantially small keratinous structures. However, little is known about the genetic basis of these specialized morphological adaptations. Here we present a 448.52-Mb genome assembly with contig N50 length of 5.53 Mb by integrating Illumina short-read sequencing, Nanopore long-read sequencing and HiC-based chromatin map. Demographic history reconstruction of the butterfly hillstream loach reveals that the population dynamics is correlated with the different stages of uplifting of the Tibetan Plateau. Comparative genomic analysis finds evidence of six keratin genes in butterfly hillstream loach evolving under positive selection. Within these genes, two keratin genes exhibit species-specific and divergent amino acid changes, suggesting a role in the formation of the unculi. Additionally, a series of positively selected genes, rapid evolving genes, specific variant genes and expanded gene families are found, including genes related to Hedgehog, Notch and BMP pathways, which may be involved in craniofacial development. These findings may have important implications for understanding the genetic basis of phenotypic adaptation to torrential mountain stream life., (© 2021 John Wiley & Sons Ltd.)

Proteins can be post-translationally modified and this can be important in the regulation of cellular processes and function. However, little is known about whether protein phosphorylation plays a role in regulating wool fibre properties. In this study, we used a chemical labelling method combined with a high performance liquid chromatography-mass spectrometry (HPLC-MS) analysis to compare the phosphopeptides present in the wool of three Tan sheep with highly crimped wool and three Tan sheep with straighter wool. Thirty-six phosphopeptides that had differences in relative abundance between these two types of wool were identified. These peptides were derived from 28 to 33 different proteins, including two keratins (Ks) and 7 to 12 keratin-associated proteins (KAPs), with these proteins being common structural components of the wool fibre. The crimped wool had a higher relative abundance of phosphorylated K38, K72 and KAP13-x, whereas the straighter wool had a higher relative abundance of phosphorylated KAP2-1, KAP6-1, KAP4-x, KAP10-x and KAP13-y. These results confirm the phosphorylation of wool Ks and KAPs, and suggest that differential phosphorylation of Ks and KAPs may affect wool fibre crimping in Tan sheep. SIGNIFICANCE: Protein phosphorylation can alter the structural conformation and interaction of a protein, and hence affect the cellular processes that the protein undertakes. In this study, we compared the suite of phosphorylated proteins in crimped and straight wool from Chinese Tan sheep and found that some keratins and keratin-associated proteins were phosphorylated. Crimped wool had more keratin phosphorylation, while straight wool had more keratin-associated protein phosphorylation, with this suggesting that wool fibre crimping may be a regulated by phosphorylation of some wool proteins. This suggests that wool traits may be under epigenetic control and that post-translation modifications need to be considered in breeding for different wool types., (Copyright © 2021 Elsevier B.V. All rights reserved.)

The keratin-associated proteins (KAPs) are constituents of cashmere fibers and variation in many KAP genes ( KRTAPs ) has been found to be associated with fiber traits. The gene encoding the high-sulphur KAP28-1 has been described in sheep, but it has not been identified in the goat genome. In this study, a 255-bp open reading frame on goat chromosome 1 was identified using a search of similar sequence to ovine KRTAP28-1 , and that would if transcribed and translated encode a high sulphur KAP. Based on the analysis of polymerase chain reaction (PCR) amplicons for the goat nucleotide sequences in 385 Longdong cashmere goats in China, five unique banding patterns were detected using single-stranded conformational polymorphism (SSCP). These represented five DNA sequences (named variants A to E ) and they had the highest resemblance to KRTAP28-1 sequences from sheep, suggesting A - E are variants of caprine KRTAP28-1 . DNA sequencing revealed a 2 or 4-bp deletion and eleven nucleotide sequence differences, including four non-synonymous substitutions. Of the four common variants ( A , B , C and D ) found in these goats, the presence of variant A was associated with decreased mean fiber diameter and this effect appeared to be additive. These results indicate that caprine KRTAP28-1 variation might have value as a molecular marker for reducing cashmere mean fiber diameter., Competing Interests: The authors declare no conflict of interest.

Esophageal cancer is a common human malignant tumor with high mortality. Glandular epithelial markers, such as CAM5.2, can be expressed in esophageal squamous cell carcinoma (ESCC), but the clinical significance of these cells in ESCC remains elusive.Immunohistochemical analysis of CAM5.2 was performed on 604 ESCC specimens using tissue microarray. Our study design and study population used retrospective cohorts based on the hospital information system and pathological information management system which included medical information, date of admission, procedures undergone, registration, examinations, and medication.In total, positive staining of CAM5.2 was 145 of 604 (24%). Statistical analysis showed that the expression of CAM5.2 had no relationship with sex, age, tumor differentiation, tumor size, tumor-node-metastasis (TNM) classification, and lymph node metastasis, but it was significantly associated with poor prognosis of overall survival (P = .0041) and disease-free survival (P = .0048) in ESCC patients.Herein, we report for the first time that the high expression of the CAM 5.2 is an independent predictor of poor prognosis in patients with ESCC.

Background: Highly diversified in morphology and structure, feathers have evolved into various forms. Frizzle feathers, which result from a developmental defect of the feather, are observed in several domestic chicken breeds. The frizzle phenotype is consistent with incomplete dominance of a major gene, but the molecular mechanisms that underlie this phenotype remain obscure. Kirin, a Chinese indigenous chicken breed that originated in the Guangdong province, is famous for its frizzle feathers. The KRT75 gene is considered as the dominant gene responsible for the frizzle trait in several chicken breeds, but this is not the case in the Kirin breed. Thus, the objective of our study was to investigate the genomic region and mutation responsible for this phenotype in this particular breed., Results: A resource population was produced by crossing Kirin and Huaixiang chickens to produce F 1 and F 2 generations. DNA samples from 75 frizzle feather and normal feather individuals were sequenced with double-digest genotyping by sequencing (dd-GBS). After the detection of 525,561 high-quality variants, a genome-wide association analysis was carried out and the gene responsible for the frizzle phenotype was localized within the type II α-keratin cluster on chromosome 33. Sanger sequencing was used to screen for mutations in the exons of five genes of this type II α-keratin cluster. A 15-bp deletion in exon 3 of KRT75L4 that showed complete segregation with the frizzle phenotype was detected within the F 2 population. Transcriptome sequencing demonstrated that KRT75L4 was expressed but that the transcript was shorter in Kirin than in Huaixiang chickens. In addition, by using Sanger sequencing, we were able to confirm that the deletion was in complete linkage with frizzle feathers., Conclusions: A deletion in the KRT75L4 gene is responsible for the frizzle feather phenotype in the Kirin chicken. The identification of this mutation, which causes a developmental defect of avian integument appendages, will improve our understanding of the mechanisms that are involved in feather formation.

Keratin-associated protein is one of the major structural proteins of the hair, whose content in hair has important effect on the quality of cashmere. In order to study the relationship between HGTKAP gene expression and cashmere fineness, the quantitative real-time RT-PCR (qRT-PCR) was firstly used to detect the levels of KAP7.1, KAP8.2 gene expression in the primary and secondary hair follicles; semi-quantitative RT-PCR was used to detect whether KAP7.1, KAP8.2 gene are expressed in heart, liver, spleen, lung, kidney tissues; and in situ hybridization(ISH) to detect KAP7.1 gene expression location. qRT-PCR result showed that the expression of both KAP7.1 and KAP8.2 gene in the secondary hair follicles are significantly higher than that in the primary follicles, relative quantitative analysis obtained that KAP7.1 was 2.28 times, while KAP8.2 was 2.71 times. Semi-quantitative RT-PCR results revealed that KAP 7.1 and KAP8.2 mRNA were not detected in the heart, liver, spleen, lung and kidney tissues, demonstrating that KAP7.1 and KAP8.2 were specially expressed in hair follicles, participating in hair formation. Moreover, KAP7.1 gene has a strong expression in the cortical layer, inner root sheath of the primary follicles and the cortical layer, inner root sheath and hair matrix of the secondary hair follicles by ISH analysis. Taken together, the evidence presented here indicated that in the formation of cashmere and wool, differential expression of these two genes in the primary and secondary hair follicles may have an important role in regulating the fiber diameter.

Shotgun proteomic analysis of the human nail plate identified 144 proteins in samples from Causcasian volunteers. The 30 identified proteins solubilized by detergent and reducing agent, 90% of the total nail plate mass, were primarily keratins and keratin associated proteins. Keratins comprised a majority of the detergent-insoluble fraction as well, but numerous cytoplasmic, membrane, and junctional proteins and histones were also identified, indicating broad use by transglutaminases of available proteins as substrates for cross-linking. Two novel membrane proteins were identified, also found in the hair shaft, for which mRNAs were detected only at very low levels by real-time polymerase chain reaction in other tissues. Parallel analyses of nail samples from volunteers from Inner Mongolia, China gave essentially the same protein profiles. Comparison of the profiles of nail plate and hair shaft from the latter volunteers revealed extensive overlap of protein constituents. Analyses of samples from an arsenic-exposed population revealed few proteins whose levels were altered substantially but raised the possibility of detecting sensitive individuals in this way.

Objective: To evaluate the diagnostic significance of detecting cytokeratin 19 (CK19) mRNA by quantitative reverse transcription polymerase chain reaction (RT-PCR) in benign and malignant pleural effusions., Methods: CK19 mRNA was examined by quantitative RT-PCR and CK19 was detected by Enzyme-linked immunoadsorbent assay (ELISA) in 32 patients with malignant pleural effusions and 35 patients with benign pleural effusions., Results: On the threshold of 200 copies/microl, the positive rate of CK19 mRNA in patients with malignant pleural effusions was 62.5%. The positive rates of CK19 mRNA and CK19 in the malignant pleural effusions were significantly higher than those in the benign group (P<0.01). Furthermore, the positive rate of CK19 mRNA was higher than that of CK19 in the malignant group (P<0.05)., Conclusion: Detection of CK19 mRNA can be a promising diagnostic marker in differential diagnosis of benign and malignant pleural effusions.

A previously undescribed missense mutation was detected in the L12 domain of keratin 5 (K5) in a Chinese family with Weber-Cockayne epidermolysis bullosa simplex. Direct sequencing of the PCR products identified a single base substitution (983A-->G) that changes the aspartic acid residue at codon 328 to glycine in all affected family members, while no mutation was observed either in the healthy individual or 50 unrelated control samples. Asp328 of K5 is remarkably conserved among all type II keratins. D328G is the fourth mutation found to affect this residue in K5-related epidermolysis bullosa simplex, indicating the importance of Asp328 for K5 structure and the dramatic effect that fine changes can have on keratin intermediate filament integrity.

Background: Epidermolytic palmoplantar keratoderma (EPPK) is an autosomal dominant inherited skin disorder characterized by diffuse yellow thickening of the skin of the palms and soles, sharply bordered with erythematous margins. Histologically and ultrastructurally, EPPK presents cytolysis of keratinocytes and abnormal aggregation of tonofilaments in the suprabasal layers of the epidermis. To date, 15 different mutations of the keratin 9 gene (KRT9) have been demonstrated to cause most cases of EPPK., Objectives: To identify the KRT9 mutation in a large Chinese family with EPPK., Methods: Denaturing high-performance liquid chromatography (DHPLC), DNA sequencing and allele-specific polymerase chain reaction (AS-PCR) were used to screen exon 1 of the KRT9 gene for sequence variations., Results: The DHPLC elution profiles of the DNA fragments amplified from the affected samples differed from those obtained from unaffected individuals, indicating that a sequence variation existed within the analysed fragment of KRT9. DNA sequencing revealed a novel insertion-deletion mutation in the exon 1 of KRT9, 497delAinsGGCT, resulting in the change of tyrosine(166) to tryptophan and leucine (Y166delinsWL). AS-PCR confirmed the mutation was not a common polymorphism., Conclusions: The results suggest the molecular basis of EPPK in this Chinese family and provide further evidence that mutations in the helix initiation motif of keratin 9 underlie Chinese EPPK.

Background: Pachyonychia congenita (PC) is a group of autosomal dominant ectodermal dysplasias caused by mutations in four differentiation-specific keratin genes. Two major clinical subtypes of PC have been generally recognized. Symmetrically thickened fingernails and toenails are the defining characteristic of PC type 2 (PC-2) with onset at infancy. Pilosebaceous cysts are the best hallmark of PC-2, but they usually occur at puberty., Objectives: To report a Chinese pedigree of PC-2 with unusually early onset sebaceous cysts and to explore the genetic mutation and its phenotype., Methods: Exon 1 of keratin 17 was amplified by polymerase chain reaction (PCR) from genomic DNA from the three patients in the pedigree, the proband, his half-sister and his younger son, two unaffected members in the pedigree and 50 unrelated and unaffected people. PCR products were directly sequenced to detect the mutation., Results: Direct sequencing of the PCR products revealed a heterozygous 275A-->G mutation in all three affected members. This mutation predicts the substitution of asparagine by serine in codon 92 (N92S) located in the 1A domain of keratin 17., Conclusions: Mutation in the 1A domain of keratin 17 underlies the affected members' phenotype, PC-2 with early onset sebaceous cysts and late-onset thickened fingernails and toenails. The onset of the cysts is very early in some people within this family and the age at onset of thickened fingernails and toenails is variable within the family, implying the existence of modifying factors.