Identification and characterization of novel alternative splice variants of human SAMD11.

Sterile alpha motif domain-containing 11 (SAMD11) is evolutionarily conserved from zebrafish to human. Mouse Samd11 is predominantly expressed in developing retinal photoreceptors and the adult pineal gland, and its transcription is directly regulated by the cone-rod homeodomain protein Crx. However, there has been little research on human SAMD11. To investigate the function of human SAMD11, we first cloned its coding sequence (CDS) and identified up to 45 novel alternative splice variants (ASVs). Mouse Samd11 ASVs were also identified by aligning the mouse Samd11 expressed sequence tags (ESTs) with the annotated sequence. However, the range of expression and transcriptional regulation of SAMD11 differs between human and mouse. Human SAMD11 was found to be widely expressed in many cell lines and ocular tissues and its transcription was not regulated by CRX, OTX2 or NR2E3 proteins. Furthermore, functional analysis indicated that human SAMD11 could promote cell proliferation slightly. In conclusion, this study elucidated the basic characteristics of human SAMD11 and revealed that, although the occurrence of alternative splicing of SAMD11 was conserved, the function of SAMD11 may vary in different species.