The human gene for g

[摘要] Purpose: gS-crystallins are major components of adultvertebrate lenses. Here we examine the population of gStranscripts in adult human lens and the structure of the human CRYGSgenes.Methods: Adult lens human transcripts were obtained from NEIBANK, anExpressed Sequence Tag (EST) analysis of human eye tissues. The humanCRYGS gene was isolated as a PAC clone and sequenced by direct andPCR-based methods.Results: As judged by EST frequency, gS is one of the mostabundant transcripts in the adult human lens, ranking just behind bB2-, aB- and aA-crystallins. EST analysis reveals twotranscript sizes resulting from alternative AATAAA and ATTAAApolyadenylation signals. In addition, one cDNA clone was found tocontain a novel insert sequence that disrupted the open reading frame.Gene sequencing confirmed that this insert comes from intron 1 and ispart of a sequence corresponding to a cluster of unidentified humantranscripts in dbEST. Human and mouse gS gene proximal promotersequences were compared and showed a high degree of evolutionaryconservation, including consensus binding sites for transcriptionfactors of the maf and SOX families.Conclusions: The human CRYGS gene can give rise to at least twotranscripts through alternative polyadenylation. A minor transcriptresults from alternative splicing into sequences in intron 1. Thesesequences form part of a transcription unit (Mys) expressed in severalnon-lens tissues. The identity and function Mys of is not yet known,however, the cryptic splicing of CRYGS could produce a defective proteinproduct, with potentially deleterious results for the adult human lens.

[学科分类] 生物化学/生物物理