Association of a hypoxia-inducible factor-3α gene polymorphism with superovulation traits in Changbaishan black cattle

Expression pattern of ZNF33B in bovine ovaries and the effect of its polymorphism on superovulation traits

ZNF33B belongs to recently duplicated Krüppel-associated box domain zinc finger proteins (KRAB-ZFPs), which is widely present in various organs, and some evidence showed that its expression is altered in the ovary undergoing superovulation. In this study, the expression of ZNF33B in ovary and early embryo was determined by immunohistochemistry and immunofluorescence techniques. Results showed that the expression of ZNF33B in the ovary was mainly in the cytoplasm of oocytes and granulosa luteal cells of ovarian corpus luteum and significantly reduced during follicular ovulation to luteal degeneration. The expression of ZNF33B in the early embryo transferred from the nucleus to the whole cell, suggesting that the expression of ZNF33B is spatiotemporally specific. Then, in combination with the single nucleotide polymorphism (SNP) database, the g.-61G>T mutant of the 5′-untranslated region (5′ UTR) of the ZNF33B gene was screened out from 556 Changbaishan black cattle, and the frequency of the mutant gene was counted. The statistics of superovulation and superovulation traits confirmed significant differences between the two genotypes in the quantity and quality of oocytes obtained after superovulation. This study confirmed, for the first time, the effect of ZNF33B gene polymorphism on superovulation traits and suggested that the mutation could provide a basis for cattle breeding and improving animal fertility.

Genome-wide identification, classification, and functional analysis of the basic helix-loop-helix transcription factors in the cattle, Bos Taurus

The basic helix-loop-helix (bHLH) transcription factors (TFs) form a huge superfamily and play crucial roles in many essential developmental, genetic, and physiological-biochemical processes of eukaryotes. In total, 109 putative bHLH TFs were identified and categorized successfully in the genomic databases of cattle, Bos Taurus, after removing redundant sequences and merging genetic isoforms. Through phylogenetic analyses, 105 proteins among these bHLH TFs were classified into 44 families with 46, 25, 14, 3, 13, and 4 members in the high-order groups A, B, C, D, E, and F, respectively. The remaining 4 bHLH proteins were sorted out as 'orphans.' Next, these 109 putative bHLH proteins identified were further characterized as significantly enriched in 524 significant Gene Ontology (GO) annotations (corrected P value ≤ 0.05) and 21 significantly enriched pathways (corrected P value ≤ 0.05) that had been mapped by the web server KOBAS 2.0. Furthermore, 95 bHLH proteins were further screened and analyzed together with two uncharacterized proteins in the STRING online database to reconstruct the protein-protein interaction network of cattle bHLH TFs. Ultimately, 89 bHLH proteins were fully mapped in a network with 67 biological process, 13 molecular functions, 5 KEGG pathways, 12 PFAM protein domains, and 25 INTERPRO classified protein domains and features. These results provide much useful information and a good reference for further functional investigations and updated researches on cattle bHLH TFs.