Alternative splicing and tissue expression of CIB4 gene in sheep testis

The Diverse Functions of the Calcium- and Integrin-Binding Protein Family

The calcium- and integrin-binding protein (CIB) family, comprising four evolutionarily conserved members (CIB1, CIB2, CIB3, and CIB4), is characterized by canonical EF-hand motifs. The functions of CIBs in the inner ear have been investigated, although further research is still necessary to gain a comprehensive understanding of them. Among the CIB family members, CIB2 is essential for auditory function. CIB3 and CIB2 jointly participate in the regulation of balance. Beyond their sensory roles, CIBs exhibit multifunctionality through calcium-dependent interactions with diverse molecular partners, contributing to the pathogenesis of various conditions, including neurological disorders, cardiovascular diseases, cancer, and male infertility. In this review, we discuss the conserved structure of the CIB family, highlighting its contributions to various biological functions. We also summarize the distribution and function of the CIB family, emphasizing the pivotal roles of CIB2 and CIB3 in hearing and balance.

CIB4 is essential for the haploid phase of spermatogenesis in mice†

Spermatogenesis is a complex developmental process that involves the proliferation of diploid cells, meiotic division, and haploid differentiation. Many genes are shown to be essential for male fertility using knockout (KO) mice; however, there still remain genes to be analyzed to elucidate their molecular mechanism and their roles in spermatogenesis. Calcium- and integrin-binding protein 1 (CIB1) is a ubiquitously expressed protein that possesses three paralogs: CIB2, CIB3, and CIB4. It is reported that Cib1 KO male mice are sterile due to impaired haploid differentiation. In this study, we discovered that Cib4 is expressed strongly in mouse and human testis and begins expression during the haploid phase of spermatogenesis in mice. To analyze the function of CIB4 in vivo, we generated Cib4 KO mice using the CRISPR/Cas9 system. Cib4 KO male mice are sterile due to impaired haploid differentiation, phenocopying Cib1 KO male mice. Spermatogenic cells isolated from seminiferous tubules demonstrate an essential function of CIB4 in the formation of the apical region of the sperm head. Further analysis of CIB4 function may shed light on the etiology of male infertility caused by spermatogenesis defects, and CIB4 could be a target for male contraceptives because of its dominant expression in the testis.

Impact of merging commercial breeding lines on the genetic diversity of Landrace pigs

BACKGROUND

The pig breeding industry has undergone a large number of mergers in the past decades. Various commercial lines were merged or discontinued, which is expected to reduce the genetic diversity of the pig species. The objective of the current study was to investigate the genetic diversity of different former Dutch Landrace breeding lines and quantify their relationship with the current Dutch Landrace breed that originated from these lines.

RESULTS

Principal component analysis clearly divided the former Landrace lines into two main clusters, which are represented by Norwegian/Finnish Landrace lines and Dutch Landrace lines. Structure analysis revealed that each of the lines that are present in the Dutch Gene bank has a unique genetic identity. The current Dutch Landrace breed shows a high level of admixture and is closely related to the six former lines. The Dumeco N-line, which is conserved in the Dutch Gene bank, is poorly represented in the current Dutch Landrace. All seven lines (the six former and the current line) contribute almost equally to the genetic diversity of the Dutch Landrace breed. As expected, the current Dutch Landrace breed comprises only a small proportion of unique genetic diversity that was not present in the other lines. The genetic diversity level, as measured by Eding's core set method, was equal to 0.89 for the current Dutch Landrace breed, whereas total genetic diversity across the seven lines, measured by the same method, was equal to 0.99.

CONCLUSIONS

The current Dutch Landrace breed shows a high level of admixture and is closely related to the six former Dutch Landrace lines. Merging of commercial Landrace lines has reduced the genetic diversity of the Landrace population in the Netherlands, although a large proportion of the original variation is maintained. Thus, our recommendation is to conserve breeding lines in a gene bank before they are merged.

Genome-Wide Variation, Candidate Regions and Genes Associated With Fat Deposition and Tail Morphology in Ethiopian Indigenous Sheep

Variations in body weight and in the distribution of body fat are associated with feed availability, thermoregulation, and energy reserve. Ethiopia is characterized by distinct agro-ecological and human ethnic farmer diversity of ancient origin, which have impacted on the variation of its indigenous livestock. Here, we investigate autosomal genome-wide profiles of 11 Ethiopian indigenous sheep populations using the Illumina Ovine 50 K SNP BeadChip assay. Sheep from the Caribbean, Europe, Middle East, China, and western, northern and southern Africa were included to address globally, the genetic variation and history of Ethiopian populations. Population relationship and structure analysis separated Ethiopian indigenous fat-tail sheep from their North African and Middle Eastern counterparts. It indicates two main genetic backgrounds and supports two distinct genetic histories for African fat-tail sheep. Within Ethiopian sheep, our results show that the short fat-tail sheep do not represent a monophyletic group. Four genetic backgrounds are present in Ethiopian indigenous sheep but at different proportions among the fat-rump and the long fat-tail sheep from western and southern Ethiopia. The Ethiopian fat-rump sheep share a genetic background with Sudanese thin-tail sheep. Genome-wide selection signature analysis identified eight putative candidate regions spanning genes influencing growth traits and fat deposition (NPR2, HINT2, SPAG8, INSR), development of limbs and skeleton, and tail formation (ALX4, HOXB13, BMP4), embryonic development of tendons, bones and cartilages (EYA2, SULF2), regulation of body temperature (TRPM8), body weight and height variation (DIS3L2), control of lipogenesis and intracellular transport of long-chain fatty acids (FABP3), the occurrence and morphology of horns (RXFP2), and response to heat stress (DNAJC18). Our findings suggest that Ethiopian fat-tail sheep represent a uniquely admixed but distinct genepool that presents an important resource for understanding the genetic control of skeletal growth, fat metabolism and associated physiological processes.

Molecular analysis of CIB4 gene and protein in Kermani sheep

The human calcium- and integrin-binding protein (CIB) family is composed of CIB1, CIB2, CIB3, and CIB4 proteins and the CIB4 gene affects fertility. Kermani sheep is one of the most important breeds of Iranian sheep breeds. The aim of this study was to analyze for the first time molecular characteristics of the CIB4 gene and protein in Kermani sheep. Different tissues were collected from the Kermani sheep and real time PCR was performed. The PCR products were sequenced, comparative analyses of the nucleotide sequences were performed, a phylogenetic tree was constructed, and different characteristics of CIB4 proteins were predicted. Real time PCR results showed that the CIB4 gene is expressed only in testis of Kermani sheep. The cDNA nucleotide sequence was identical with small tail Han sheep, cattle, goat, camel, horse, dog, mouse and human, respectively 100, 99, 99, 98, 98, 96, 96, and 96%. Hence, it can be suggested that the CIB4 gene plays a role in male fertility. Based on the phylogenetic analysis, sheep CIB4 gene has a close relationship with goat and cattle first, and then with camel and whale. Although we demonstrated that CIB4 is a testis-specific gene, expressed only in the testis and it interacts with other proteins, the mechanisms by which CIB4 expression is regulated need to be elucidated.

Genome-wide association study provides strong evidence of genes affecting the reproductive performance of Nellore beef cows

Reproductive traits are economically important for beef cattle production; however, these traits are still a bottleneck in indicine cattle since these animals typically reach puberty at older ages when compared to taurine breeds. In addition, reproductive traits are complex phenotypes, i.e., they are controlled by both the environment and many small-effect genes involved in different pathways. In this study, we conducted genome-wide association study (GWAS) and functional analyses to identify important genes and pathways associated with heifer rebreeding (HR) and with the number of calvings at 53 months of age (NC53) in Nellore cows. A total of 142,878 and 244,311 phenotypes for HR and NC53, respectively, and 2,925 animals genotyped with the Illumina Bovine HD panel (Illumina^®, San Diego, CA, USA) were used in GWAS applying the weighted single-step GBLUP (WssGBLUP) method. Several genes associated with reproductive events were detected in the 20 most important 1Mb windows for both traits. Significant pathways for HR and NC53 were associated with lipid metabolism and immune processes, respectively. MHC class II genes, detected on chromosome 23 (window 25-26Mb) for NC53, were significantly associated with pregnancy success of Nellore cows. These genes have been proved previously to be associated with reproductive traits such as mate choice in other breeds and species. Our results suggest that genes associated with the reproductive traits HR and NC53 may be involved in embryo development in mammalian species. Furthermore, some genes associated with mate choice may affect pregnancy success in Nellore cattle.

Roles of small RNAs in the effects of nutrition on apoptosis and spermatogenesis in the adult testis

We tested whether reductions in spermatozoal quality induced by under-nutrition are associated with increased germ cell apoptosis and disrupted spermatogenesis, and whether these effects are mediated by small RNAs. Groups of 8 male sheep were fed for a 10% increase or 10% decrease in body mass over 65 days. Underfeeding increased the number of apoptotic germ cells (P < 0.05) and increased the expression of apoptosis-related genes (P < 0.05) in testicular tissue. We identified 44 miRNAs and 35 putative piRNAs that were differentially expressed in well-fed and underfed males (FDR < 0.05). Some were related to reproductive system development, apoptosis (miRNAs), and sperm production and quality (piRNAs). Novel-miR-144 (miR-98), was found to target three apoptotic genes (TP53, CASP3, FASL). The proportion of miRNAs as a total of small RNAs was greater in well-fed males than in underfed males (P < 0.05) and was correlated (r = 0.8, P < 0.05) with the proportion of piRNAs in well-fed and underfed males. In conclusion, the reductions in spermatozoal quality induced by under-nutrition are caused, at least partly, by disruptions to Sertoli cell function and increased germ cell apoptosis, mediated by changes in the expression of miRNAs and piRNAs.

Nutrition affects Sertoli cell function but not Sertoli cell numbers in sexually mature male sheep

We tested whether the reversible effects of nutrition on spermatogenesis in sexually mature sheep were mediated by Sertoli cells. Rams were fed with diets designed to achieve a 10% increase (High), no change (Maintenance) or a 10% decrease (Low) in body mass after 65 days. At the end of treatment, testes were lighter in the Low than the High group (PP<0.05) in the expression of seven Sertoli cell-specific genes. Under-nutrition appeared to reverse cellular differentiation leading to disruption of tight-junction morphology. In conclusion, in sexually mature sheep, reversible reductions in testis mass and spermatogenesis caused by under-nutrition were associated with impairment of basic aspects of Sertoli cell function but not with changes in the number of Sertoli cells.

Calcium- and integrin-binding protein-1 is down-regulated in the sperm of patients with oligoasthenozoospermia : CIB1 expression in patients with oligoasthenozoospermia

PURPOSE

The aim of this study was to determine whether altered expression and distribution of calcium- and integrin-binding protein-1 (CIB1) is involved in the pathogenesis of patients with oligoasthenozoospermia.

METHODS

Sperm samples were obtained from 25 infertile Chinese men who had failed to achieve conception after a period of 1-2 y and had been referred to the Reproductive Laboratory of the second hospital affiliated to the Shandong University of Traditional Chinese Medicine. Participants were divided into two groups: oligoasthenozoospermia (n = 13) and asthenozoospermia (n = 12); as a third group, fertile men (n = 19) were included as controls. The expression levels of mRNA and protein levels of CIB1 and cyclin-dependent kinase 1 (CDK1) were measured using qRT-PCR and western blotting.

RESULTS

mRNA and protein expression levels of CIB1 were decreased in the oligoasthenozoospermia patients. Interestingly mRNA and protein expression levels of CDK1 were increased in the oligoasthenozoospermia patients.

CONCLUSION

The results of the present study indicate that that CIB1 may be involved in the pathogenesis of oligoasthenozoospermia by the CDK1 signaling pathway.

Biophysical and structural studies of the human calcium- and integrin-binding protein family: understanding their functional similarities and differences

The human calcium- and integrin-binding protein 1 (CIB1) plays important roles in various cellular functions. In this study, three other members of this protein family (CIB2-4: CIB2, CIB3, and CIB4) were purified and subsequently characterized using biophysical and structural approaches. As expected from sequence alignments, CIB2-4 were shown to bind calcium (Ca(2+)) and magnesium (Mg(2+)) ions. Binding of Ca(2+) or Mg(2+) ions changes the secondary structure of CIB2-4 and the exposure of hydrophobic surface area. Ca(2+) and Mg(2+) ions also stabilize the tertiary structures for CIB2 and CIB3. Through in vitro binding experiments, we show that CIB2 can interact with the integrin αIIb cytoplasmic domain and the integrin α7b membrane-proximal fragment. Fluorescence experiments using a 7-azatryptophan labeled peptide demonstrate that CIB2, CIB3, and CIB4 are binding partners for the integrin αIIb subunit, which suggests that they are potentially involved in regulating integrin αIIb subunit activation. The distinct responses of αIIb to the different CIB3 and CIB4 metal (Ca(2+) and Mg(2+)) binding states imply a potential connection between the calcium and integrin signaling pathways.