Phylogenetic analyses of 41 Y-STRs and machine learning-based haplogroup prediction in the Qingdao Han population from Shandong province, Eastern China.

BACKGROUND: Known for its rich history and culture, Qingdao is a typical symbol of Chinese maritime culture. Its unique genetic landscape has aroused interest among geneticists and forensic scientists. However, the genetic landscape of Qingdao has never been uncovered. AIM: This investigation intends to provide light on Qingdao's paternal genetic diversity and its evolutionary connections to other Han subgroups. SUBJECTS AND METHODS: The genetic polymorphisms of 41 Y-chromosomal short tandem repeat (STR) loci in the Qingdao Han were investigated using SureID® PathFinder Plus Kit. Phylogenetic studies were performed using genotype data from 52 East Asian groups at 23 common Y-STR loci. A multidimensional scaling plot and cladogram were constructed. Linear Discriminant Analysis (LDA) was carried out for predicting categories among the Han people. The k-nearest neighbour (kNN) algorithm was utilised to designate Y-SNP haplogroups for each haplotype. RESULTS: The Qingdao Han were genetically far from the Tibeto-Burman populations and close with the Han people from northern China. LDA indicated a deep integration among the present-day Han people. By the kNN model, the predicted O2a2 and O2a1 were shown to be the predominant Y-SNP haplogroups. CONCLUSIONS: This study would be helpful for reconstructing the patrilineal history in China and establishing a more comprehensive Y-STR database.

Effects of Nt-truncation and coexpression of isolated Nt domains on the membrane trafficking of electroneutral Na+/HCO3- cotransporters.

The SLC4 genes are all capable of producing multiple variants by alternative splicing or using alternative promoters. The physiological consequences of such diversity are of great interest to investigators. Here, we identified two novel variants of the electroneutral Na(+)/HCO3- cotransporter NBCn1, one full-length starting with "MIPL" and the other Nt-truncated starting with "MDEL". Moreover, we identified a new promoter of Slc4a10 encoding NBCn2 and a novel type of Nt-truncated NBCn2 starting with "MHAN". When heterologously expressed, the new NBCn1 variants were well localized to the plasma membrane and exhibited characteristic NBCn1 activity. However, MHAN-NBCn2 was poorly localized on the plasma membrane. By deletion mutations, we identified the Nt regions important for the surface localization of NBCn2. Interestingly, coexpressing the full-length NBCn2 greatly enhances the surface abundance of the Nt-truncated NBCn2. Co-immunoprecipitation and bimolecular fluorescence complementation studies showed that the full-length and Nt-truncated NBCn2 interact with each other to form heterodimers in neuro-2A cells. Finally, we showed that the isolated Nt domain interacts with and enhances the surface abundance of the Nt-truncated NBCn2. The present study expands our knowledge of the NBCn1 and NBCn2 transcriptome, and provides insights into how the Nt domain could affect transporter function by regulating its membrane trafficking.

Cloning and functional characterization of novel variants and tissue-specific expression of alternative amino and carboxyl termini of products of slc4a10.

Previous studies have shown that the electroneutral Na(+)/HCO(3) (-) cotransporter NBCn2 (SLC4A10) is predominantly expressed in the central nervous system (CNS). The physiological and pathological significances of NBCn2 have been well recognized. However, little is known about the tissue specificity of expression of different NBCn2 variants. Moreover, little is known about the expression of NBCn2 proteins in systems other than CNS. Here, we identified a set of novel Slc4a10 variants differing from the originally described ones by containing a distinct 5' untranslated region encoding a new extreme amino-terminus (Nt). Electrophysiology measurements showed that both NBCn2 variants with alternative Nt contain typical electroneutral Na(+)-coupled HCO(3) (-) transport activity in Xenopus oocytes. Luciferase reporter assay showed that Slc4a10 contains two alternative promoters responsible for expression of the two types of NBCn2 with distinct extreme Nt. Western blotting showed that NBCn2 proteins with the original Nt are primarily expressed in CNS, whereas those with the novel Nt are predominantly expressed in the kidney and to a lesser extent in the small intestine. Due to alternative splicing, the known NBCn2 variants contain two types of carboxyl-termini (CT) differing in the optional inclusion of a PDZ-binding motif. cDNA cloning showed that virtually all NBCn2 variants expressed in epithelial tissues contain, but the vast majority of those from the neural tissues lack the PDZ-binding motif. We conclude that alternative transcription and splicing of Slc4a10 products are regulated in a tissue-specific manner. Our findings provide critical insights that will greatly influence the study of the physiology of NBCn2.