ABSTRACT
Amelogenesis imperfecta (AI) comprises a group of rare, inherited disorders with abnormal enamel formation. Ameloblastin (AMBN), the second most abundant enamel matrix protein (EMP), plays a critical role in amelogenesis. Pathogenic biallelic loss-of-function AMBN variants are known to cause recessive hypoplastic AI. A report of a family with dominant hypoplastic AI attributed to AMBN missense change p.Pro357Ser, together with data from animal models, suggests that the consequences of AMBN variants in human AI remain incompletely characterized. Here we describe 5 new pathogenic AMBN variants in 11 individuals with AI. These fall within 3 groups by phenotype. Group 1, consisting of 6 families biallelic for combinations of 4 different variants, have yellow hypoplastic AI with poor-quality enamel, consistent with previous reports. Group 2, with 2 families, appears monoallelic for a variant shared with group 1 and has hypomaturation AI of near-normal enamel volume with pitting. Group 3 includes 3 families, all monoallelic for a fifth variant, which are affected by white hypoplastic AI with a thin intact enamel layer. Three variants, c.209C>G; p.(Ser70*) (groups 1 and 2), c.295T>C; p.(Tyr99His) (group 1), and c.76G>A; p.(Ala26Thr) (group 3) were identified in multiple families. Long-read AMBN locus sequencing revealed these variants are on the same conserved haplotype, implying they originate from a common ancestor. Data presented therefore provide further support for possible dominant as well as recessive inheritance for AMBN-related AI and for multiple contrasting phenotypes. In conclusion, our findings suggest pathogenic AMBN variants have a more complex impact on human AI than previously reported.
Subject(s)
Amelogenesis Imperfecta , Dental Enamel Proteins , Animals , Humans , Amelogenesis/genetics , Amelogenesis Imperfecta/genetics , Dental Enamel Proteins/genetics , Dental Enamel Proteins/metabolism , Pedigree , PhenotypeABSTRACT
The complete nucleotide sequences of RNA 1 and RNA 2 of the nepovirus potato black ringspot virus (PBRSV) from two different isolates were determined, as well as partial sequences from two additional isolates. RNA1 is 7,579-7,598 nucleotides long and contains one single open reading frame (ORF), which is translated into a large polyprotein with 2,325 amino acids and a molecular weight of 257 kDa. The complete sequence of RNA2 ranges from 3857 to 3918 nt between the different isolates. It encodes a polyprotein of 1079-1082 amino acids with a molecular weight of 120 kDa. Sequence comparison using the Pro-Pol region and CP showed that all four isolates formed two distinct groups, corresponding to potato and arracacha, that were closely related to each other and also to tobacco ringspot virus (TRSV). Comparing our data to those obtained with other nepoviruses, our results confirm that PBRSV belongs to a distinct species and is a member of subgroup A in the genus Nepovirus based on its RNA2 size, genome organization, and nucleotide sequence.
Subject(s)
Genome, Viral , Nepovirus/classification , Nepovirus/genetics , RNA, Viral/genetics , Sequence Analysis, DNA , Cluster Analysis , Molecular Sequence Data , Molecular Weight , Nepovirus/isolation & purification , Open Reading Frames , Phylogeny , Sequence Homology , Solanum tuberosum/virology , Viral Proteins/chemistry , Viral Proteins/geneticsABSTRACT
This study reports the first complete genome sequence of Piper yellow mottle virus (PYMoV, KC808712) identified in black pepper. The genome is 7,622 nucleotides long, possessing four open reading frames (ORFs). ORF1, ORF2 and ORF4 of PYMoV are reported as hypothetical proteins of unknown function with a predicted molecular mass of 15.7, 17.1 and 17.9 kDa, respectively. ORF3 of PYMoV encodes a polyprotein of 218.6 kDa and consists of a viral movement protein (MP), trimeric dUTPase, zinc finger, retropepsin, RT-LTR, and RNAse H. Detailed PYMoV genome analysis confirmed that it is a member of the family Caulimoviridae, genus Badnavirus. Fragments of two additional novel sequences resembling those found in members of the family Caulimoviridae were also identified in the black pepper sample, and the viruses from which they were derived were tentatively named Piper DNA virus 1 and 2.
Subject(s)
Badnavirus/genetics , DNA, Viral/chemistry , DNA, Viral/genetics , Genome, Viral , Badnavirus/isolation & purification , Molecular Sequence Data , Molecular Weight , Open Reading Frames , Piper nigrum/virology , Sequence Analysis, DNA , Viral Proteins/chemistry , Viral Proteins/geneticsABSTRACT
The complete genome sequences of RNA1 and RNA2 of the oca strain of the potato virus arracacha virus B were determined using next-generation sequencing. The RNA1 molecule is predicted to encode a 259-kDa polyprotein with homology to proteins of the cheraviruses apple latent spherical virus (ALSV) and cherry rasp leaf virus (CRLV). The RNA2 molecule is predicted to encode a 102-kDa polyprotein which also has homology to the corresponding protein of ALSV and, to a lesser degree, CRLV (30 % for RNA1, 24 % for RNA2). Detailed analysis of the genome sequence confirms that AVB is a distinct member of the genus Cheravirus.
