Cloning, expression and subcellular localization of HN1 and HN1L genes, as well as characterization of their orthologs, defining an evolutionarily conserved gene family

Abstract

The present work reported the cloning and characterization of two novel human genes--HN1 (hematopoietic- and neurologic-expressed sequence 1) and HN1L (HN1-like gene) which are proposed to be involved in embryo development. HN1 is mapped on chromosome 17q25.2, with two transcripts (1.0 and 1.6 kb in length, respectively) due to alternative splicing. HN1 is expressed abundantly in testis and skeletal muscle among 16 human tissues, and it is localized in the nucleus indicated by GFP fusion expression. Western blot confirmed that HN1 encodes a 16.5-kDa protein. HN1L is on chromosome 16p13.3, with three splicing in the length of 2.0, 4.0 and 4.2 kb, respectively. HN1L is expressed in a variety of tissues such as liver, kidney, prostate, testis and uterus at varying levels. HN1L gene encodes a 20-kDa protein, which is localized in both the nucleus and cytoplasm. Fourteen of HN1 and sixteen of HN1L homologous genes in different species were determined and analyzed by BLAST searches. Silicon analyses of the 14 orthologous proteins of HN1 and 16 orthologous proteins of HN1L revealed that they share great conservation in vertebrate. Additionally, we identified nine pseudogenes of HN1 (six) and HN1L (three) in the genomes of the human, mouse and rat. Based on sequence alignments and phylogenetic analysis, all these homologous genes and pseudogenes were defined as a HN1 gene family.